Question

Hi! Would one of you please check my work? Thanks! ( I used significant digits, by the way)

A student throws a 5.00 kg steel shot directly upwards so that it leaves his hand when it is 2.00 m above the ground. If its velocity is 0.15 m/s when it leaves his hand, calculate:

1.The shot's potential energy in the student's hand before he throws it

* I got 98.1 J

2.The work done to accelerate it to 15.0 m/s

* I got 98.1 J

3. The kinetic energy when it leaves his hand

* I got 5.6 * 10^-2 J

4. The total mechanical energy of the shot

* I got 98.2 J

5. The height above his hand where it stops rising

* I got 0.00115 m


6. The height above the ground at that point

* I got 2.00115 m


7. The potential energy relative to the ground at that point

* I got 98.16 J

8. The kinetic energy just before it strikes the ground

*I got 98.16

9. The velocity with which it strikes the ground

* I got 6.3 m/s

Answer 1

you seem to have both 15 and .15 for the velocity. Compromise at 1.5 maybe?

Answer 2

Hmmm... The worksheets lists both 0.15 and 15 as velocity (?)Perhaps they forgot to put the decimal.

Will I not get a different answer if the velocity is different, like you suggested?

Thanks!

Answer 3

1. Correct

3. Correct

5. Correct

6. Correct.

7. Correct

8. Correct

9. Correct.

Answer 4

Thanks you Henry! I still would like to know if 2 and 4 are correct, thank you!

Answer 5

2 and 4 are correct as are others using 0.15 for initial velocity up. However I am quite sure that was not the intent because the velocity is so low it makes little sense and the shot hardly gets above the hand.

Answer 6

Thanks! I will have to ask my teacher about the low velocity bit..

Answer 7

Yes, I noticed that the initial velocity
was unusually low; but I assumed that a
change in velocity would change the
answer but not the procedure.