Question

A body is projected vertically up with velocity 10m/s reaches a height of 20 m. if it is projected with a velocity of 2om/s,then the maximum height reached by body is

Answer 1

The height will be maximum when the velocity becomes 0 because of gravity.
Therefore, v=0
Now we will evaluate acceleration working on the object.

Using the formula: $v^{2} - u^{2} =2as$
we get,
 0-100=40a
 4a=-10
 a=-2.5$m/ s^{2}$

Now,
u=20
v=0
a=-2.5

Using the same formula as before,
 $-400=-5h$
 5h=400
 h=80 metres