Q:- Why is it easier to roll a barrel than to pull it?
Ans:- This is due to the concept of friction. As the rolling force of friction is less than the dynamic force of sliding friction therefore it is easier to roll a barrel than to pull it.
Q:- If a feather, a wooden ball and a steel ball fall simultaneously in a vacuum, which one of these would fall faster?
Ans:- All will fall at the same speed in vacuum because there will be no air resistance and the earth’s gravity (acceleration due to gravity = 9.8 m/s2) will exert a similar gravitational pull on all.
Q :- Which is more elastic, steel or rubber?
Ans:- If the question is about the Modulus of Elasticity then steel is more elastic for the same stress produced in rubber.
Elasticity also means that if an object is stretched with certain force then it will come back to its original shape after the removal of the force.
Regarding stretching, no doubt rubber is more stretchable than steel.
Q:- Why does ink leak out of a partially filled pen when taken to a higher altitude?
Ans:- You may probably know that with increase in height or altitude the pressure and density of air decreases.
Therefore, when a partially filled pen taken to a higher altitude leaks because the pressure of air acting on the ink inside the tube of the pen is greater than the pressure of the air outs