Question

A ball is thrown with intital energy 100 J at an angle​

Answer 1

Explanation:

A ball is thrown with initial energy [Math Processing Error] [Math Processing Error] at an angle [Math Processing Error] to the horizontal. If its energy at the top becomes [Math Processing Error] [Math Processing Error] then angles of projection-

Answer 2

Answer:

Intial energy = ½mu2= 100J …..........(1)

where m- mass of the ball and u-velocity with which it is thrown.

At the top most point there is only horizontal component of velocity (ucosθ) and its vertical compnent will be zero.

So energy at the top most point = ½mu2cos2θ = 30

=> 100cos2θ = 30 (using equation (1))

=> cosθ = (30/100)1/2 = (3/10)1/2

=> θ=cos-1(3/10)½