Question

LAST QUESTION FOR MY FINALS

How far does a model rocket accelerating at +40m/s^2 go in 2 seconds if launched from rest?

Answer 1

• Initial velocity=u=0m/s
• Acceleration=a=40m/s^2
• Time=t=2s
• Distance=s

Apply second equation of kinematics

`\\ \tt\longmapsto s=ut+(1)/(2)at^2`

`\\ \tt\longmapsto s=(1)/(2)(40)(2)^2`

`\\ \tt\longmapsto s=20(4)`

`\\ \tt\longmapsto s=80m`

Answer 2

According to the Given Statement

Acceleration a of model rocket is + 40m/s²

Time for the rocket accelerate t is 2 s

Its initial velocity u is 0m/s ( it is at rest )

We have to calculate the height attained by rocket .

Using Kinematic Equation

• h = ut + ½ at²

On substituting the value we obtain

➥ h = 0×2 + ½ × 40 × 2²

➥ h = 0 + 20 × 4

➥ h = 80m

So, the height attained by the rocket is 80 metres.