Question

A boy lifts a mass of 5 kg to a height of 125 cm. If the force of gravity on a mass of 1 kg is 10 N, find the work done by the boy. Q2. A body of mass 10 kg is at the height of 2 m. It is raised further to a height of 4 m. Calculate the increase in the gravitational potential energy of the body. ​

Answer 1

Answer:

1) mass = 5kg

height = 1.25m

g = 10m/s²

force on the body = 50N

therefore, procedure 1:-

W = d × F

= 1.25 × 50

= 62.5J

procedure 2:-

W = mgh

= 5×10×1.25

= 62.5 J

2) mass = 10kg

height (initial) = 2m

g = 10m/s²

therefore, gravitational potential energy (initial) =

10×10×2 = 200J

height final = 4m

therefore, gravitational potential energy (final) =

10×10×4 = 400J

hence increase in gravitational potential energy of the body => 400J - 200J = 200J

Hope it helped :)