Question

A man holds a child on his shoulders while watching a football match. How many work has he done if the game lasts for 2 hours? ​

Answer 1

Answer: ZERO!

work= F•d = F*d*cos(theta)

Since there is no displacement taking place then there is NO WORK being done! Cheers!

Answer 2

very interesting and amazing question u had asked but i get it...

Answer

• work done is given by

W = Force × Displacement

• but in above case force is exerted on the men as the weight of the child × gravitational pull of earth (9.8 m/s^2) but the displacement or movement is ZERO
• there for W= F×0 =0
• so even after carrying child for 2 hours work done by the men will be zero

More examples

• a person standing straight and lifting weight
• a person carry some weight and walk in a circular path and came back to its original position.........in this case also Displacement will be zero

------------------------------------

hope it helped u buddy