Question
A heavy trunk is lying on the floor. A boy applies a force of 100 N to pull it, but fails. Then a man pulls it by a force of 300 N, but fails. Then an athlete applies a force of 600 N and is able to pull it. What force does it prevent from moving in the first two cases ? What conclusions can you draw about the force from these three observations?
Solution
Given, that the trunk is very heavy. So, the force of friction between the trunk and the floor prevents the motion in the first two cases.
So, the force of friction is greater than 300 N but less than 600 N.
