# Newton's Laws of Motion

Tags:
1. Oct 26, 2014

1. The problem statement, all variables and given/known data
A truck (1200kg) is travelling south at 22m/s
a) what is the net force required to bring the truck to a stop in 330m?
b) what is the cause of this net force? (im assuming the answer is friction due to brakes)

Mass= 1200kg (1.2*10^4)
Velocity= 22m/s [south]
What force is required to stop the object (1200kg) in 330 meters?

2. Relevant equations

anything needed to solve the equation?

3. The attempt at a solution

ΣF= m*a
=1200kg * a

a= ( 22 m/s [south] ) / Δt

330m/22m= Δt
t=15 seconds

a= 22/15
a = 1.4666667

"a" is now the number of meters per second required to decelerate to reach fnet = 0 ?

Unsure if this is on the right track or extremely off what I need to do for a question like this

Last edited: Oct 26, 2014
2. Oct 26, 2014

### rude man

(a) Think energy conservation. Kinetic energy change to heat.
(b) you're right.

3. Oct 26, 2014

### vela

Staff Emeritus
OK up to here.

$x = vt$ only works when there's no acceleration.