Question

Pam has a mass of 44.9 kg and she is at rest on

smooth, level, frictionless ice. Pam straps on
a rocket pack. The rocket supplies a constant
force for 20.5 m and Pam acquires a speed of
62 m/s.
What is the magnitude of the force?

Answer 1

• Mass=m=44.9kg
• Distance=s=20.5m
• initial velocity=u=0m/s
• Final velocity=v=62m/s
• Force=F
• Acceleration=a

Using third equation of kinematics

`\\ \tt\longmapsto v^2-u^2=2as`

`\\ \tt\longmapsto a=(v^2-u^2)/(2s)`

• u=0

`\\ \tt\longmapsto a=(v^2)/(2s)`

`\\ \tt\longmapsto a=(62^2)/(2(20.5))`

`\\ \tt\longmapsto a=(3844)/(41)`

`\\ \tt\longmapsto a=93.7m/s^2`

Apply Newton's second law

`\\ \tt\longmapsto F=ma`

`\\ \tt\longmapsto F=44.9(93.7)`

`\\ \tt\longmapsto F=4207.2N`