Question 152: Motion in 2D & Vectors

Question

A body is projected from the ground at an angle of 45$$^\circ$$ with the horizontal. Its velocity after 2s is 20 ms$$-$$1. The maximum height reached by the body during its motion is __________ m. (use g = 10 ms$$-$$2)

Accepted Answer

$$ \Rightarrow v\cos \alpha  = u\cos 45^\circ $$ ..... (i)
& $$v\sin \alpha  = u\sin 45^\circ  - gt$$ ..... (ii)
Solve for u we get
$$u = 20\sqrt 2 $$ m/s
$$ \Rightarrow H = {{{u^2}{{\sin }^2}45^\circ } \over {20}} = 20$$ m

Motion in 2D & Vectors

A body is projected from the ground at an angle of 45$^\circ with the horizontal. Its velocity after 2s is 20 ms-1. The maximum height reached by the body during its motion is __________ m. (use g = 10 ms-$2)

Choose the correct answer: