A ball projected from ground vertically upward is at same height at time t1 and t2 the speed - Physics - Motion In A Straight Line

Question

A ball projected from ground vertically upward is at same height
at time t1 and t2 the speed of projection of ball is

Jyoti Pant · Accepted Answer

Suppose the height travelled by ball in the time t1 and t2 is h
and the speed of projection is u
Then, using relation
s=ut+12at2We have,h=ut1-12gt12and h=ut2-12gt22(Acceleration is taken negative as it acts downwards i
e opposite direction of motion)so, ut1-12gt12=ut2-12gt22 ut1-ut2=12gt12-12gt22u(t1-t2)=12g (t12-t22)u=g (t12-t22)2(t1-t2)=g((t1+t2)2

A ball projected from ground vertically upward is at same height at time t1 and t2 . the speed of projection of ball is