Question

A ball is thrown upwards from the ground with an initial speed of u. The ball is at a height of 80 mat two times, the time interval being 6s. Find u. Take g = 10 m/s² .

Answer 1

Here, u = u m/s, a = g = – 10 m/s² and s = 80 m.

Substituting the value in s = ut + 1/2 at², we have

Now, it is given that

Ignoring the negative sign, we have

u = 50 m/s