Question

a body is thrown with some velocity from the ground maximum height when it is thrown at 60 degree to the horizontal is 90 metre what is the height reached when it is thrown at 30 degree to the horizontal

Answer 1

A body is thrown with some velocity from the ground.Maximum height when it is thrown at 60° to horizontal is 90 m. What is the height reached when it is thrown at 30° to the horizontal.

Answer 2

Given that,

When angle of projection is 60 degree, the maximum height reached by the body is 90 metre.

To find,

The height reached when it is thrown at 30 degree to the horizontal.

Solution,

The formula used to find the maximum height reached by the projectile is given by :

$H=\dfrac{u^2\sin^2\theta}{2g}$

When H = 90 metre, $\theta=60^{\circ}$,

$90=\dfrac{u^2\sin^2(60)}{2g}\ .....(1)$

Let H' is height when  $\theta=30^{\circ}$

So,

$H'=\dfrac{u^2\sin^2(30)}{2g}\ ....(2)$

From equation (1) and (2) we get :

$\dfrac{90}{H'}=\dfrac{\sin^2(60)}{\sin^2(30)}\\\\\dfrac{90}{H'}=3\\\\H'=30\ m$

So, when the angle of projection is 30 degrees, the maximum height reached by the body is 30 metre.