Question

A boy has a bag of sand of mass 20kg, first of all, he keeps the bag on his head and move
10 metre. Second time, he drags the bag through 10 metre on a frictionless surface. In
which case, he does more work.​

Answer 1

Answerin dragging it on polished surface

Explanation: because the angle between the displacement and force is 90 degree thus cos 90 becomes zero and thus work done becomes zero

Answer 2

Answer:

because angle is 40degree