PreAP Physics
posted by Mandy on .
Pam has a mass of 40Kg and she is at rest on smooth, level, frictionless ice. Pam Straps on a rocket pack. The rocket supplies a constant force for 22m and Pam acquires a speed of 62 m/s.
A) What is the magnitude of the force?
B) What is Pam's final Kinetic Energy?

First compute the time t that the force acts.
Vaverage*t = Vfinal*t/2
= (31 m/s)*t = 22 m
t = 0.7097 s
a = Vfinal/t = 62/0.7097 = 87.4 m/s^2
F = M a = ?
Final KE = (1/2) M Vfinal^2
(That part ie easy!) 
To: DRWLS,
I got 3500 Newtons for part A? What am I doing wrong? 
I get about the same answer for Part A.

I did not use time in my equation. I used Force * Distance= change KE for Part A and got the 3500 Newtons.
What am I doing wrong? 
There is nothing wrong with your answer or method that I can see. I got the same answer (to three significant fgures) with a different method.