Question

the speed of a projectile at its maximum height is half of its initial speed. The angle of projectile os

a) 60

b) 15

c) 30

d) 45

Answer 1

a is the answer to the question

Answer 2

At maximum height, only horizontal velocity exists. Thus,

$\displaystyle\longrightarrow\sf{u\cos\theta=\dfrac{u}{2}}$

$\displaystyle\longrightarrow\sf{\cos\theta=\dfrac{1}{2}}$

$\displaystyle\longrightarrow\sf{\underline{\underline{\theta=60^o}}}$