Newton's Laws of Motion

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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.