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3 years ago

14

A car accelerates from 20mi/hr to 60mi/hr. How many times greater is the car's kinetic energy at the higher speed compared to th

e kinetic energy at the slower speed

1 answer:

Ainat [17]3 years ago

4 0

Answer:

9 times

Explanation:

Kinetic energy is:

KE = ½ mv²

When we triple the velocity, the kinetic energy increases by a factor of 9.

9KE = ½ m(3v)²

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Use the drop-down menus to complete the sentences.

Grace [21]

Answer:

1) thinner, diverge

2) thicker, converge

Explanation:

i got it right

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2 years ago

Read 2 more answers

Carbon is allowed to diffuse through a steel plate 9.7-mm thick. The concentrations of carbon at the two faces are 0.664 and 0.3

cupoosta [38]

Answer:

844°C

Explanation:

The problem can be easily solve by using Fick's law and the Diffusivity or diffusion coefficient.

We know that Fick's law is given by,

$J = - D \frac{\Delta c}{\Delta x}$

Where $\frac{\Delta c}{\Delta x}$ is the concentration of gradient

D is the diffusivity coefficient

and J is the flux of atoms.

In the other hand we have, that

$D= D_0 e^{\frac{E_d}{RT}}$

Where $D_0$ is the proportionality constant,

R is the gas constant, T the temperature and $E_d$ is the activation energy.

Replacing the value of diffusivity coefficient in Fick's law we have,

$J = -D_0 ^{\frac{E_d}{RT}}\frac{\Delta c}{\Delta x}$

Rearrange the equation to get the value of temperature,

$T=\frac{Ed}{Rln(\frac{J\Delta x}{D_0 \Delta c})}$

We have all the values in our equation.

$\Delta c = 0.664-0.339 = 0.325 C. cm^{-1}$

$\Delta x = 9.7*10^{-3}m$

$E_d = 82000J$

$D_0 = 6.5*10^{-7}m^2/s$

$J = 3.2*10^{-9}m^2/s$

$R= 8.31Jmol^{-1}K$

Substituting,

$T=\frac{Ed}{Rln(\frac{J\Delta x}{D_0 \Delta c})}$

$T=-\frac{-82000}{(8.31)ln(\frac{3.2*10^{-9}(9.7*10^{-3})}{6.5*10^{-7} (0.325)})}$

$T=1118.07K=844\°C$

4 0

3 years ago

Wrapping paper is being unwrapped from a 5.0-cm radius tube, free to rotate on its axis. if it is pulled at the constant rate of

lisov135 [29]

So the equation for angular velocity is

Omega = 2(3.14)/T

Where T is the total period in which the cylinder completes one revolution.

In order to find T, the tangential velocity is

V = 2(3.14)r/T

When calculated, I got V = 3.14

When you enter that into the angular velocity equation, you should get 2m/s

5 0

3 years ago

A cannonball is fired horizontally at the same time a ball being dropped from the same height How do the times it takes them to

ipn [44]

Answer:

The cannonball and the ball will both take the same amount of time before they hit the ground.

Explanation:

For a ball fired horizontally from a given height, there is only a vertical acceleration on it towards the ground. This acceleration is equal to the acceleration due to gravity (g = 9.81 m/s^2). A ball dropped from a height will also only experience the same vertical acceleration downwards which is also equal to g = 9.81 m/s^2.

Therefore both the cannonball and the ball will take the same amount of time to hit the ground if they are released/fired from the same height.

3 0

3 years ago

What is the direction of the magnetic field around a wire carrying a current perpendicularly into this page

UNO [17]

Answer:

Clockwise direction

Explanation:

In a case of a wire carrying a current, the right hand rule is used.

The thumb in the direction of current while the finger curl around in the direction of the magnetic field.

The right hand rule applies to a current in a straight line wire.

If the direction a wire carrying a current perpendicularly into this page, the direction of the magnetic field will be in a clockwise direction .

3 0

3 years ago