Physics High School

## Answers

**Answer 1**

**Answer:**

-4568.25 m/s (2 d.p.)

**Explanation:**

As we need to find the y-component of the** initial velocity**, consider the vertical and horizontal motion of the electron separately.

Trigonometry can be used to **resolve **the body's motion into its vertical and horizontal components:

Horizontal component of u = u cos θVertical component of u = u sin θ

Vertical component of acceleration:

[tex]\sf a_y=a \sin\theta = 5200 \sin(55^{\circ})\:\:\sf ms^{-2}[/tex]

Vertical component of final velocity:

[tex]\sf v_y=v \sin \theta=6598 \sin (-20.5^{\circ})\:\:\sf ms^{-1}[/tex]

[tex]\boxed{\begin{minipage}{9 cm}\underline{SUVAT}\\\\s = displacement in m (meters)\\u = initial velocity in ms$^{-1}$ (meters per second)\\v = final velocity in ms$^{-1}$ (meters per second)\\a = acceleration in ms$^{2}$ (meters per second per second)\\t = time in s (seconds)\\\end{minipage}}[/tex]

Therefore:

[tex]\sf u=u_y\\ v=6598 \sin (-20.5^{\circ})\\a=5200 \sin(55^{\circ})\\ t=0.530[/tex]

To find the vertical component of the initial velocity (u):

[tex]\begin{aligned}\textsf{Using }\:\:v&= u+at\\\\\implies \sf 6598 \sin (-20.5^{\circ}) & = \sf u_y+5200 \sin(55^{\circ})(0.530)\\\sf u_y & = \sf 6598 \sin (-20.5^{\circ})-5200 \sin(55^{\circ})(0.530)\\\sf \implies u_y& = \sf -4568.251336...m/s\end{aligned}[/tex]

Therefore, the **y-component** (vertical component) of the **initial velocity** is **-4568.25 m/s (2 d.p.)**.

## Related Questions

Piston 2 has a diameter of 8.83 cm. In the absence of friction, determine the force F, necessary to support an object with a mass of 812 kg placed on piston 2. (Neglect the height difference between the bottom of the two pistons, and assume that the pistons are massless).

### Answers

The** force** F, necessary to support an object with a mass of 812kg placed on piston 2 is **404.17 N**.

What is Pascal's law?

According to** Blaise Pascal's** law, a **pressure** change in a confined, incompressible fluid that happens at any place is distributed evenly throughout the fluid, causing the identical change to occur everywhere.

Calculation of the force needed to support the mass :

[tex]\frac{F_{1} }{A_{1} } =\frac{F_{2} }{A_{2} }[/tex]

[tex]\frac{F_{1} }{d_{1} ^{2} } =\frac{F_{2} }{d_{2} ^{2} }[/tex]

[tex]F_{1} =\frac{F_{2}d_{1} ^{2} }{d_{2} ^{2} }[/tex]

Where

[tex]F_{2}[/tex] is force exerted on piston 2, F = mg

g = 9.8 m/[tex]s^{2}[/tex]

[tex]d_{2}[/tex] is given diameter of piston 2, = 8.83 cm

[tex]d_{1}[/tex] is given diameter of piston 1, = 1.99 cm

So the force [tex]F_{1}[/tex] on piston 1 = ?

[tex]F_{1}[/tex] = (812 x 9.8 x [tex]0.0199^{2}[/tex])/ [tex](0.0883)^{2}[/tex]

[tex]F_{1}[/tex] = 404.17 N

Hence, the force F, necessary to support an object with a mass of 812 kg placed on piston 2 is** 404.17 N**.

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Fernanda is working on a physics project. she is experimenting by rolling a marble down a ramp and then seeing how far it rolls along the floor after leaving the ramp. which would be the dependent variable in fernanda’s experiments? the angle of the ramp the length of the ramp the distance the marble rolls after the ramp the direction that gravity makes the marble roll

### Answers

The **distance covered **on the floor after leaving the ramp is the **dependent variable**.

As a result of the marble's size, the substance it is constructed of, and the **angle** at which it is placed onto the ground, the distance it rolls varies. Therefore, the** angle **at which the marble is released onto the ground, the type of material used to make the stone, or its size can all be considered **independent variables**.What is Independent variable?There are **independent** and **dependent** variables in every experiment. A **variable **is considered independent if its change is not influenced by the change in another variable or factor.What is Dependent variable?

In any experiment, the **dependent variable **must be measured or determined, and it must change as the **independent variable** does.

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A(n)_________is a metallic or nonmetallic box installed in an electrical wiring system from which current istaken to supply some apparatus or device.

### Answers

A(n) **outlet box** is a **metallic** or **nonmetallic** box installed in an **electrical wiring** system from which current is taken to supply some **apparatus** or device.

**Handy boxes** come in one- and **two-gang** variants and are designed for indoor use. For fixing the box to a wall or a **ceiling** framework member, some contain a mounting bracket.

What is an outlet box ?

An **electrical terminal box** where **cables** are terminated before being connected to electrical **installations** or appliances

**Electrical devices** must normally be encased in an appropriate electrical box, as are the **wiring** connections to such devices, according to **electrical codes**. This metal or plastic box, often called a **junction box,** has a cover to protect the wire inside and shield you from the wiring.

**Electrical outlets** or **switches** are frequently installed on exposed surfaces using handy boxes, also known as **utility boxes**.

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A football is kicked from the ground with a speed of 16.71 m/s at an angle of 49.21 degrees. What is the vertical component of the initial velocity?

### Answers

If a **football **is kicked from the ground with a speed of 16.71 m/s at an angle of 49.21 degrees, then the **vertical **component of the initial velocity would be 12.65 m/s

What is Velocity?

The total displacement covered by any object per unit of **time **is known as velocity. It depends on the magnitude as well as the direction of the moving object. The unit of velocity is meter/second.

As given in the problem A football is **kicked **from the ground with a speed of 16.71 m/s at an angle of 49.21 degrees

The horizontal **component **of the velocity is given by

Vx = Vcosθ

The **vertical **component of the velocity is given by

Vy = Vsinθ

As we have to find the vertical component of the velocity given that speed of 16.71 m/s at an angle of 49.21 degrees from the ground

Vy = 16.71 × sin49.21°

Vy = 12.65 m/s

Thus, the **vertical **component of the **velocity **would be 12.65 m/s

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A spherical tank of radius R meters is full of water. If the density of water is rho and gravitational acceleration is g, Find the work required to pump the water out from the top of the sphere.

### Answers

The answer is the **work **required to pump the water out from the top of the sphere is [tex]\Delta E=W=\frac{4}{3} \pi R^{4} \rho g \text {. }[/tex]

When the tank is full, the water inside takes the shape of a sphere with a radius R.

To calculate its mass, multiply its volume by its **density**. A sphere's volume is [tex]V=\frac{4}{3} \pi R^{3}[/tex]

Then the mass of our sphere is

Because the sphere is perfectly symmetrical, the centre of mass of the water is at the centre of the sphere, hence it is R meters below the tank's top.

To pump the water out, we must 'pull' its centre of mass to the height of the tank's top. During this process, the potential energy of the water will be altered. This distinction will be equal to

[tex]\Delta E=m g \Delta h[/tex]

In our case,

[tex]\Delta E=\frac{4}{3} \pi R^{3} \rho g R=\frac{4}{3} \pi R^{4} \rho g[/tex]

The water will also gain kinetic energy during this operation, but it is zero at the start and finish, thus the difference is likewise zero. As a result, any effort done results in a change in potential energy.

[tex]\Delta E=W=\frac{4}{3} \pi R^{4} \rho g \text {. }[/tex]

What is **density?**

The **density** of material shows the denseness of that material in a specific given area. A material’s density is defined as its mass per unit volume. **Density** is a measurement of how closely stuff is packed together. It is a distinct physical attribute of a certain thing. Archimedes, a Greek scientist, developed the density principle. If you know the formula and understand the units, calculating **density** is simple. The sign indicates **density**, which may also be represented by the letter D.

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Optics of the eye: the closest object that a typical young person with normal vision can focus on clearly is closest to:______.

### Answers

The **human eye** is one of the most valuable sense organ. The closest object that a typical young person with **normal vision** can **focus** closest to is 25 cm

The **lens in the eye** forms the image on the retina. The image formed is real and inverted. The **retina** is a very delicate membrane containing numerous light sensitive cells.

This light sensitive cells gets activated when light falls on it and generates electric signals. These electric signals are sent to the brain via the optic nerves present in the eye. The brain finally processes these signals and thus we see the object clearly.

The ability of the lens of the eye to adjust its focal length accordingly is called the **power of accommodation**,

The minimum distance, at which the object can be seen clearly without any strain is called the **least distance of distinct vision**.

To see an object clearly without any strain is when we place it at about 25 cm from the eye.

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To the surprise of michelson and morley, their interferometer experiment provided evidence that the speed of light is?

### Answers

**Answer:**

To the surprise of Michelson and Morley, their interferometer experiment provided evidence that the speed of light is. all of the above.

**Explanation:**

A wire carries a current in the x-direction. a positively charged particle moves in the –x-direction near the current-carrying wire. in what direction will the charged particle feel a magnetic force?

### Answers

A **magnetic field** is experienced by the charged particle in the +y direction.

Discussion:

The right thumb rule states that the **magnetic field** lines will be perpendicular in the area to the conductive wire's left in which the electric potential is traveling.The direction of the current may be determined by looking at the positive charge's (X direction) motion. According to Fleming's left-hand rule, the force on a positive charge will be in the +y direction because the positive charge is moving in a leftward direction, which will also be the direction of the current.

Fleming's left-hand rule:

In accordance with Fleming's Left Hand Rule, the thumb, forefinger, and middle finger of the left hand should be positioned perpendicular to one another. The thumb should point in the path of the power exerted by the conductors, the forefinger should point in the **magnetic field** direction, and the middle finger should point in the path of the electric current.

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If your engine begins to lose power, run rough, stall, or refuse to start when traveling at high altitudes, your vehicle may be suffering from _______.

### Answers

**Vapor lock**

If your engine begins to lose power, run rough, stall, or refuse to start when traveling at high altitudes, your vehicle may be suffering from **Vapor lock.**

How is vapor lock fixed?By first pressing the **accelerator** **pedal** slightly (but not all the way to the floor) while starting the **engine**, you can aid in the **removal** of any **vapor** that may have remained in the** fuel system** after it has **cooled**. Hold down the **accelerator** pedal once the **engine** fires up until the **car** moves **smoothly**, which shows the** vapor lock **has passed.

What brings about a vapor lock?When **fuel** boils in the **carburetor** or** fuel line**, **vapor lock **results. **Fuel** that has **vaporized** stops **gas** from reaching your **engine** by creating back **pressure** in your **fuel system. **It frequently happens after **idling** or after **turning off **and back on a **vehicle**.

What is the duration of vapor lock?The **heat** builds up toward the **gasoline** lines as you** shut down.** Fuel in the lines could begin to **evaporate** in the **absence** of **airflow **through the **cowling**. **Vapor lock** typically occurs when you try to **restart** your **aircraft **after a **sharp turn** (**shut down** and **restart** after about 30 minutes).

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Use the drop-down menus to indicate the stage of technological design in which each action would occur.

Establish criteria and prepare the initial design. = Design a solution.

Redesign and retest as necessary. = Evaluate a solution.

Define a need and research related information. = identify a problem.

Build and test a prototype. = implement a solution

### Answers

**Engineering design **has to do with the overall process of the **design **and the **production **of new products.

**What are the stages in engineering design?**

**Engineering design **has to do with the overall process of the **design **and the **production **of new products. Now the process of engineering design involves many components and all these are taken into account when a new product is being designed.

As such, the stage of **technological design** in which each action would occur is;

Define a need and research related information- ** identify a problem**

Establish criteria and prepare the initial design - **Design a solution**

Build and test a prototype -** implement a solution**

Redesign and retest as necessary - **Evaluate a solution**

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**answer: 1 design a solution 2 evaluate a solution 3 identify a problem 4 implement a solution **

**Explanation: i know**

Stretch a copper wire so that it is thinner and the resistance between its ends Stretch a copper wire so that it is thinner and the resistance between its ends decreases. increases. remains unchanged.

### Answers

Stretch a copper wire so that it is thinner and the **resistance **between its ends remains unchanged.

Resistance is proportional to** resistivity **and length, and inversely proportional to cross sectional area. Resistivity can be defined as the resistance of a conducting material per unit length with unit area of cross section.

Resistance = rho * (L/A)

rho = resistivity

L = length of wire

A = Cross section 'area of wore

if copper wire get stretched , length of wire will increase but due to thinning area of cross section get decreased

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A car of mass 1535 kg collides head-on with a parked truck of mass 2000 kg. Spring mounted bumpers ensure that the collision is essentially elastic. If the velocity of the truck is 17 km/h (in the same direction as the car's initial velocity) after the collision, what was the initial speed of the car

### Answers

A car of mass 1535 kg collides head-on with a parked truck of mass 2000 kg. Spring mounted bumpers ensure that the **collision **is essentially elastic. If the velocity of the truck is 17 km/h (in the same direction as the car's initial velocity) after the **collision**, what was the initial speed of the car 20kmh

What is **collision ?**

A **collision **in physics is any situation in which two or more bodies quickly exert forces on one another. Despite the fact that the most common usage of the word "**collision**" refers to situations in which two or more objects clash violently, the scientific usage of the word makes no such **assumptions**.

The following are a few instances of physical encounters that scientists might classify as **collisions**:

Legs of an insect are said to collide with a leaf when it falls on one.Every contact of a cat's paws with the ground while it strides across a lawn is seen as a **collision**, as is every brush of its fur with a blade of grass.

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What is the smallest particle that relains

the properties of an element

### Answers

**Answer:**

atom

**Explanation:**

Smallest particle of an element that identifies that element is an atom.

You and your friend are pushes hard against a stationary wall. If you push 3 times harder than your friend, then the amount of work you do is

### Answers

**Answer:**

Work = F * s where s is the distance F moves

Since F is stationary, in this case, **"no work" **is done by either person

Kathy drew a timeline to show some of the major events that occurred during the evolution of the universe. a timeline with the smallest time labeled as big bang occurred 0s, quarks and electrons formed 10 superscript negative 10 baseline seconds, protons and neutrons formed 300 seconds, nebulae formed 3000 years and hydrogen and helium formed 300000 years. which best describes kathy’s error? quarks and electrons formed at 10–35 s, not 10–10 s. protons formed first, then neutrons formed at 100 s. nebulae formed around 109 y after hydrogen and helium formed. hydrogen and helium were created at 3000 s, before nebulae formed.

### Answers

**Nebulae **formed about 109 years after **hydrogen **and helium formed, which is the statement that most accurately sums up **Kathy's **mistake. The third option is the best answer.

What is the universe?

The entire **cosmic **system of matter and energy is the universe. The universe is made up of the Earth, the **Sun**, the Moon, the planets, the stars, as well as dust, **gases**, and rocks.

As given in the problem **Kathy **drew a timeline to show some of the major **events **that occurred during the evolution of the universe. a timeline with the smallest time labeled as big bang occurred 0s, quarks and **electrons **formed 10⁻¹⁰ baseline seconds, protons and neutrons formed 300 seconds, nebulae formed 3000 years and **hydrogen **and helium formed 300000 years

Thus, **Nebulae **developed about 109 years after hydrogen and helium originated, which best sums up Kathy's **mistake**. Therefore the correct answer is option C.

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Which tuning fork test evaluates conductive and sensorineural hearing loss in both ears at the same time

### Answers

The **Rinne and Weber tests **are frequently used to detect conductive and sensorineural deafness.

Another test to assess conductive and sensorineural hearing impairments is the **Weber test**. When sound waves cannot flow from the middle ear to the inner ear, conductive hearing loss results.

This may be brought on by issues with the eardrum, middle ear, or ear canal, such as an infection. A helpful, quick, and easy screening test for determining hearing loss is the **Weber test**.

The test can identify unilateral sensorineural and conductive hearing loss. Conduction hearing is mediated by the middle and outer ear. A tuning fork is used in the **Weber test**, a hearing screening procedure. It can identify unilateral sensorineural hearing loss and unilateral conductive hearing loss in the middle ear.

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A string with mass density equal to 0.0025 kg/m is fixed at both ends and at a tension of 290 n. Resonant frequencies are found at 558 hz and the next one at 744 hz. What is the length of the wire?

### Answers

The **length** of the wire is = 0.92 meter

How can we find the value of the wire?

Here we use the formula,

[tex]f=\frac{V}{2l}[/tex]

Or, [tex]f=\frac{1}{2l} \times \sqrt{\frac{T}{\mu} }[/tex]

We know, [tex]V=\sqrt{\frac{T}{\mu} }[/tex], so we put the value of V in first equation and found the second equation.

We are given, f= Fundamental** frequency** = [tex]f_{2} -f_{1}[/tex]=(744-558)Hz= 186Hz.

V= **Velocity **of the wire.

T= **Tension **of the wire.=290N.

[tex]\mu[/tex]= **Mass density **of the wire = 0.0025 kg/m

We have to find,** length **of the wire = l

Now we substitute the known values in the equation, we get:

[tex]f=\frac{1}{2l} \times \sqrt{\frac{T}{\mu} }[/tex]

Or, [tex]186=\frac{1}{2l} \times \sqrt{\frac{290}{0.0025} }[/tex]

Or,[tex]l=\frac{1}{372} \times \sqrt{\frac{290}{0.0025} }[/tex]

Or,[tex]l=0.92 m[/tex]

So, from the above calculation we can conclude that the **length of the wire** is 0.92 meter.

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a 1 kg ball is confined to move on a. vertical circle of a radius 2 meters. There is no friciton between the bead and the circular track. The bead has a speed of 10 m/s when at the top of the circle at point A, adn the total

### Answers

The total **centripetal force** is 50N

Given

mass of the ball= 1kg

speed of the ball = 10m/s

Radius = 2m

we know that

**centripetal force** = F =[tex]\frac {mv^2}{r}[/tex]

F = [tex]\frac {1 \times {10}^2}{2}[/tex] = 50 N

**What is Centripetal force?**A force that causes a body to follow a curved path is known as a **centripetal force**.It always moves in a direction that is the opposite of the body's velocity and in the direction of the immediate center of curvature of the path. It is "a force by which bodies are dragged or driven, or in any other way gravitate, towards a point as to a center," according to Isaac Newton.Gravity is the **centripetal force** that drives astronomical orbits according to Newtonian mechanics.

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Question:

a 1 kg ball is confined to move on a. vertical circle of a radius of 2 meters. There is no friction between the bead and the circular track. The bead has a speed of 10 m/s when at the top of the circle at point A, find the total **centripetal force**.

Unpolarized light of intensity I0 is incident on two polarizing filters. The transmitted light intensity is I0/10.

### Answers

theta = 63.43 degrees

[tex]I_{0}[/tex] = intensity of unpolarized beam incident on first polaroid sheet

the intensity of the transmitted light after passing first polarizer = [tex]I_{0}[/tex]/2

given final intensity =0.1[tex]I_{0}[/tex]

=> 0.1[tex]I_{0}[/tex] = 0.5[tex]I_{0}[/tex][tex]cos^{2}[/tex](∅)

=>[tex]cos^{2}[/tex](∅) = 0.2

∅ = [tex]63.43^{0}[/tex]

**What is polarizing filters?**

In order to darken skies, control reflections, or reduce glare from lakes or the sea, a polarizing **filter or polarising filter** (see spelling variants) is frequently placed in front of the camera lens. A linear polarizer can be used to alter the lighting in a picture since reflections (and skylight) frequently include some linear **polarization**. For the desired artistic impact, the filter's rotational orientation is changed. Modern cameras frequently include circular polarizers (CPLs), which are made up of a linear **polarizer **that performs the artistic function as mentioned, followed by a quarter-wave plate that further converts the light from linear to circular **polarization** before it enters the camera.

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Suppose that the light carries energy ElightElightE_light . What is the maximum stopping potential V0V0V_0 that can be applied while still allowing electrons to reach the detector

### Answers

The stopping potential is the** electric potential** at which the electrons must cross in order to reach the detector after moving from a higher to a lower electric potential.

An expelled electron's initial kinetic energy must be more than or equal to the energy it will lose while passing across the potential difference in order for it to reach the detector. When the incident light energy exceeds the work potential of the metal on which the light is focussed, the **stopping potential**, also known as the cut-off potential, is necessary to prevent the removal of an electron from the metal surface. The strength of incident radiation has no bearing on stopping potential. The value of saturated current rises with intensity while the stopping potential stays constant. The stopping potential relies on the frequency for a particular radiation intensity. The value of stopping potential increases with the frequency of incident light.

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A force of 12,000 n is exerted on a piston that has an area of 0.020 m 2 . what is the area of a second piston that exerts a force of 24,000 n? (2 points)

### Answers

The area of the second piston is **0.04 m^2**.

What is pressure ?

**Pressure **is the term used to describe the physical force exerted on an object. A **perpendicular force** is applied to the surfaces of the objects **per unit area**. The basic formula for pressure is **F/A**. (Force per unit area). A pressure measurement is in **Pascals **(Pa).

For** piston 1**

Given **force **= 12000 N

**Pressure **= 12000 N / 0.020 m^2

=600000 N/m^2

Now, **force **at **piston 1 **must be **equal **to **force **at **piston 2**.

therefore

for** piston 2**

24000 N = 600000 N/^2 x Area

=> 24000 / 600000 m^2 = Area

=** 0.04 m^2**

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Next, consider a scientific law known as the ideal gas law. this law deals with the relationship between temperature and pressure of a fixed mass of gas. the law states that the product of the pressure (p) and volume (v) is proportional to the temperature (t) of the mass of gas. the equation can be expressed this way, with k as a constant value: pv = kt based on this equation, what are the two possible outcomes of heating up a certain mass of air?

### Answers

As the **temperature **rises, the **pressure **or **volume **of the gas rises as well. This is due to the ideal gas law, which states that pressure and volume are directly proportional to temperature and the second outcome is that the value of k remains **constant**.

The** ideal gas law**, also called the** general gas equation**, is the equation of state of a** hypothetical ideal gas**. It is a good approximation of the behaviour of many gases under many conditions, although it has several limitations. It was first stated by **Benoit Paul Emile Clapeyron** in 1834 as a combination of the empirical **Boyle's law**, **Charles's law**, **Avogadro's law**, and **Gay-Lussac's law**. The ideal gas law is often written in an empirical form:

[tex]{\displaystyle PV=nRT}{\displaystyle PV=nRT}[/tex]

where P, V and T are the pressure, volume and temperature, n is the amount of substance; and R is the ideal gas constant. It can also be derived from the **microscopic kinetic theory**.

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**Answer: The pressure of the gas or the volume of the gas will increase as the temperature increases. That’s because, according to the ideal gas law, pressure and volume are directly proportional to temperature. The value of k does not change.**

**This is straight from Edmentum so don't copy fully**

An irregularly shaped object that is 10 m long is placed with each end on a scale. If the scale on the right reads 96 N while the scale on the left reads 71 N how far from the left end is the center of gravity of this object

### Answers

**Answer:**

The left end is the center of gravity was 25N

A stone is dropped from the edge of a roof, and hits the ground with a velocity of -160 feet per second. How high (in feet) is the roof

### Answers

The answer is **400ft**

**Velocity **of a practical is increases as due to increase of inertia and also increasing of gravitational force.

solution we known that

[tex]v^{2} -u^{2} =2gh[/tex]

where , U = initial velocity

V = final velocity

G = acceleration due to gravity

let considered , G = 32

H = height of roof

[tex](-160)^{2}[/tex] - 0 = 2×32×h

** = **[tex](-160)^{2}[/tex]/ 64

H =** 400ft**

What is **velocity** ?

Its a directional speed of a object in a motion formula = displacement/ time

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A plane electromagnetic wave of frequency 20 GHz moves in the positive y-axis direction such that its electric field is pointed along the z-axis. The amplitude of the electric field is 10 V/m. The start of time is chosen so that at t

### Answers

A plane **electromagnetic wave** of frequency 20 GHz moves in the positive y-axis direction such that its electric field is pointed along the z-axis. The amplitude of the electric field is 10 V/m. The start of time is chosen so that at t

When an electric field interacts with a magnetic field,** electromagnetic waves** are created. Therefore, they are referred to as "**electromagnetic" waves.** An **electromagnetic wave's** electric field and magnetic field are perpendicular to one another (at right angles).

An electromagnetic spectrum is a group of waves with similar characteristics to **electromagnetic waves.** All **electromagnetic wave**s are transverse waves, capable of moving through a vacuum, and moving at the same speed in a vacuum, which is 300,000,000 times the speed of light.

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Tommy is planning his science fair project. he wants to measure the rate of photosynthesis in plants that live in fresh water. is this an example of a scientific investigation or an experiment?

### Answers

An **experiment** because it does not ask a **testable** **question**.

For instance, the student might outline the **procedures** for placing the plants in similar pots, the amounts of water and sunlight that will be provided for each plant, and the **frequency** and amount of fertiliser that will be applied to each plant.

What is scientific investigation ?

A **plan** for **raising questions** and putting **potential** **solutions** to the test is a scientific research. Observations are frequently the first step in a **scientific research**. Questions frequently follow observations. A **hypothesis** is a potential explanation for a scientific question based on current scientific understanding.

The goals of scientific research are to produce **knowledge** and **develop** **hypotheses**. Many different types of persons and environments are used to perform **scientific inquiries**. Scientific research is carried out in a variety of ways that depend on the gathering of various kinds of evidence.

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An object weighs 94.1 N in air. When it is suspended from a force scale and completely immersed in water the scale reads 15.8 N. Determine the density of the object. (in kg/m^3)

### Answers

The density of the object is 1203 kg/m³.

**Density** is degree of **consistency** measured by the quantity of mass per unit volume.

Given,

Weight in Air = 94.1 N

Weight in water = 15.8 N

We need to calculate the volume of the object

using formula of buoyant force

**Fb = W(air) - W(water) =** 94.1 - 15.8 = **78.3 N**

Fb = ρgh

Put the value into the formula

78.3 = 1000 X V X 9.8

V = 78.3/(1000X9.8) = 7.98 X 10⁻³

To calculate **density**

using the formula of **buoyant force**

**Fb = ρVg**

ρ = Fb/Vg = 78.3/(7.98 X 10⁻³ X 9.8) = 1203 kg/m³

Therefore, density of the object is **1203 kg/m³**

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The kinetic energy, k, of an object varies jointly with its mass, m, and the square of its velocity, v. the mass of an object stays the same, but the velocity of the object is halved. how is the kinetic energy of the object affected?

### Answers

The kinetic energy of the object is affected in that, The kinetic energy is **quartered.**

What is Kinetic Energy ?

The **energy **an item has as a result of **motion **is known as **kinetic energy **in physics. It is described as the effort required to move a** mass-determined body** from rest to the indicated **velocity**. The body holds onto the kinetic energy it acquired during its acceleration until its speed changes.

We are told that kinetic energy, K, of an object varies jointly with its mass, m, and the square of its velocity, v. Thus;

K = mv²

Now, mass is same but velocity halved. Thus, we now have;

K = m(v/2)²

K = ¹/₄mv²

Thus, the kinetic energy is quartered.

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**Answer:**

A

**Explanation:**

He said so

The type of radiation that is characterized by the emission of a particle composed of 2 protons and 2 neutrons is called _________________.

### Answers

The type of **radiation** that is characterized by the emission of a particle composed of 2 **protons** and 2 **neutrons** is called **alpha** **emissions**

Alpha radiation is a type of radioactive decay or emission in which the **atomic nucleus** emits an alpha particle thereby transforming or decaying into a new atomic nucleus.

As a matter of fact, in **alpha** **emission**, the atomic mass number of the newly formed atom will be reduced by **four** and the atomic number will be reduced by **two**.

What is radioactivity?

Radioactivity can simply be defined as the **emission** of ionizing radiation or **particles** caused by the **spontaneous disintegration** of atomic nuclei.

Generally, there are three types of **radiation**, which are:

Alpha emissionBeta emissionGamma radiation.

So therefore, the the type of alpha radiation is **characterized** by the emission of a particle composed of 2 **protons** and 2 **neutrons** is called **alpha ****emissions**

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If the eye is nearsighted, what power eyeglasses should be used for normal vision? (the eye can see faraway objects when relaxed, and also focus on an object at x = 2. 0. )

### Answers

The** power **of the eyeglasses is 0.5 **diopter**.

To find the answer, we have to know about the** power of lens.**

How to find the power of the eyeglasses?**Power of a lens **is a measure of the convergence or divergence, which a lens introduces in the light falling on it.To find the power of lens, we have the equation,

[tex]P=1/f[/tex]

where; f is the focal length of the lens, and here it is given as 2m for far objects.

Thus, the power of lens will be,

[tex]P=1/2=0.5D[/tex]

Thus, we can conclude that, the** power **of the eyeglasses is 0.5 **diopter**.

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