anonymous one year ago A mover hoists a 200 kg piano from the ground to a height of 10 m using a single pulley. What was the change in the piano's energy? A. 20 J B. 200 J C. 2,000 J D. 20,000 J

1. anonymous

@Michele_Laino :)

2. Michele_Laino

the requested potential energy change is equal to the work done by mover hoists

3. rvc

W=F X displacement

4. anonymous

so our solution is 200 J ? choice B?

5. rvc

W = 200 X 10

6. anonymous

oh! so 2000, choice C is our solution?

7. Michele_Laino

no, since 200 Kg is the mass of the piano. The work is: $\Large W = 200 \times 9.81 \times 10 = ...Joules$

8. rvc

yep need to convert

9. anonymous

oh so we get 19620? so choice D, 20,000 J is our solution?

10. Michele_Laino

correct!

11. rvc

yep

12. anonymous

yay!! thank you both!!

13. Michele_Laino

:)