JEE PYQ: Motion In Two Dimensions Question 13
Question 13 - 2020 (08 Jan Shift 2)
A particle of mass $m$ is dropped from a height $h$ above the ground. At the same time another particle of the same mass is thrown vertically upwards from the ground with a speed of $\sqrt{2gh}$. If they collide head-on completely inelastically, the time taken for the combined mass to reach the ground, in units of $\sqrt{\frac{h}{g}}$ is:
(a) $\sqrt{\frac{1}{2}}$ (b) $\sqrt{\frac{3}{4}}$ (c) $\frac{1}{2}$ (d) $\sqrt{\frac{3}{2}}$
Show Answer
Answer: (d)
Solution
After collision, combined mass has zero velocity at height $3h/4$. Time to fall: $t_1 = \sqrt{3h/(2g)}$.
BETA
