Question

A body is projected at an angle of 30 0 to the horizontal with a velocity of 150 ms-1. Calculate the time it takes to reach the maximum height. [ Take g= 10ms-2 ; neglect air resistance ]

Answer 1

Answer:

7.5 sec

Explanation:

For the vertical motion of the body:

velocity = vsinθ = (150)(sin30°)

               = 75 m/s

At the highest point, velocity is 0.

 Using the equations of motions,

⇒ v = u + at

⇒ 0 = 75 + (-g)(t)

⇒ 75/g = t

⇒ 75/10 = t  = 7.5 sec

it takes 7.5 seconds to reach the maximum height

Answer 2

Given :-

Angle = 30

Velocity = 150 m/s

To Find :-

Time taken

Solution :-

At first finding final velocity

vsinθ  = 150/sin30

• sin30 = 30

v = 150/30

v = 5 m/s

Now

v = u + gt

5 = 0 + 10(t)

5 = 10t

5/10 = t

0.5 = t

Time taken is 0.5 sec