Question

A rocket accelerates upward at a rate of 28.5 m/s until it reaches a height of 100 meters above the ground where the engine shuts down. What is the maximum height the rocket will obtain?

Answer 1

We know the equation of motion

  

Where, v is final velocity of the object

u is initial velocity of the object

a is acceleration of the object

S is total displacement of the object

For the given problem (after the 100 m journey),

u = 28.5 m/s (when engine stops the velocity of rocket was 28.5 m/s)

v = 0 m/s (at maximum height)

a = -g = -9.8 m/s² (acceleration due to gravity)

Putting all the values in the equation of motion, we get

or,

or,

Hence, the maximum height reached by the rocket is 100 + 41.44 = 141.44 m .