Question

A wooden block is dropped from the top of a cliff 100 metre high and simultaneously a bullet of mass 10 gram is fired from the foot of the cliff upwards with a velocity of 100 m/s . The bullet and wooden block will meet each other after a time

Answer 1

Let they meet after t second
If block travels 's'm distance then in same time the bullet travells(100-s)m
For block
s=0×t+1/2×10×t^2
For bullet
100−s=100×t+1/2(−10)×t^2
Solving this we get t=1second