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3 years ago

How can the potential energy in magnets be used to create kinetic energy in an object without making contact?

1 answer:

7 0

Answer: If you move a magnet quickly through a coil of copper wire, the electrons will move - this produces electricity.

Explanation:

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Can someone help me on no. 6

liq [111]

Efficiency = (energy that does the job) / (total energy used)

= (45 J) / (120J)

I think you can handle the division.

8 0

3 years ago

I would like help with this physics problem

Darina [25.2K]

(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.

Recall that

$v_f=v_i+at$

We have $v_f=-v_i$ , so that

$-2v_i=at\implies-2\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)=\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)t\implies t=8\,\mathrm s$

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.

(d) The position of the ball $x_f$ at time $t$ is given by

$x_f=x_i+v_it+\dfrac12at^2$

Take the starting position to be the origin, $x_i=0$ . Then after 6 seconds,

$x_f=\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)(6\,\mathrm s)+\dfrac12\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)(6\,\mathrm s)^2=42\,\mathrm m$

so the ball is 42 m away from where it started.

We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

$x_f-x_i=\dfrac{v_i+v_f}2t\implies42\,\mathrm m=\dfrac{8\,\frac{\mathrm m}{\mathrm s}+v_f}2(6\,\mathrm s)\implies v_f=6\,\dfrac{\mathrm m}{\mathrm s}$

Since the velocity is positive, the ball is still moving up the incline.

8 0

3 years ago

PLEASE HELP <br> IS THIS CORRECT?

Umnica [9.8K]

Answer:

yes!

Explanation:

7 0

3 years ago

Read 2 more answers

A tool use to quickly develop quality database design by reusing commonly available data models which are applicable to the ente

Trava [24]

U can be helped at flash cards

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3 years ago

Explain why the several different types of microscopes are all neccassary?

Sphinxa [80]

Answer:

The different types of microscopes are all necessary because not all experiments require the same level of magnification. ... All microscopes allow visualization of samples that are too small to be viewed by the naked eye.

Explanation:

$hii$
have a nice day

7 0

3 years ago