## ashna 3 years ago A potter moving vertically up the stairs with a suitcase on his head does work . why ?

1. akash123

try it by ur own...I'll help u

2. ashna

but i dont know and that is why i asked this question , give me the hints :)

3. ashna

and if you dunt mind can you teach me all types of questions like dis ?

4. akash123

1st make a block of mass m as I did in last question...

5. akash123

|dw:1348895105918:dw|

6. akash123

and coolie is holding it on his head...right?

7. ashna

yes right !

8. akash123

now u have to tell...who or what is exerting force on this load?

9. akash123

1st earth is pulling towards its center by force mg..right?

10. ashna

N

11. ashna

YES

12. akash123

|dw:1348895307961:dw|

13. akash123

and u have to find out..work done by the potter?

14. akash123

and the potter is exerting a force N on the load and the direction of force is vertically upward.

15. akash123

again work done by potter= Force. displacement = N *( displacement) * cos(theta)

16. ashna

vertical so cos 0 = 1

17. akash123

now this time u have to tell the value of theta if potter is moving vertically up

18. akash123

yes...perfectly right...:)

19. akash123

so potter has done some work...because work done is not equal to zero

20. ashna

yeah , okay ty :D

21. akash123

:)