Posted by Jason on Saturday, September 14, 2013 at 2:21am.
a driver of a 1200kg car notices that the car slows from 20 m/s to 15 m/s as it coasts a distance of 130 m along level ground. How large a force opposes the motion? Show the solution

Mechanics  Graham, Saturday, September 14, 2013 at 4:39am
Given:
m = 1200kg
u = 20m/s
v = 15m/s
s = 130m
Use:
v = u + at
s = ut + (at^2)/2
F = ma
Solve the velocity equation for time (t).
Substitute this into the displacement equation to solve for acceleration (a).
Multiply acceleration by mass (m) to give force (F).