Question

Give reasons:
(i) When we strike at the bottom of a pile of coins, only the lowest coins move.
A long jumper runs slowly at first and then speeds up before he takes a leap.​

Answer 1

Answer:

The reason is that as the striker hits the lowest coin, it moves (i.e., changes its state of rest), while the remaining pile remains intact at rest and takes the place of the original pile.

long jumper runs slowly at first and then speeds up before he takes a leap? An athlete always runs some distance before taking a jump to gain momentum. The rate of change of momentum, due to this, becomes lesser so he can jump longer distance with same force.