JEE Main Physics Class 11 Motion in a Straight Line and Plane Part 1 Questions

For uniformly accelerated/ deaccelerated motion :
v2=u2±2gh
As equation is quadratic, so, v−h graph will be a parabola Initially velocity is downwards (–ve) and then after collision it reverses its direction with lesser magnitude, i.e. velocity is upwards (+ve).
Note that time t = 0 corresponds to the point on the graph
where h = d.
Next time collision takes place at 3.