Question

A 2500‐kg vehicle traveling at 25 m/s can be stopped by gently applying the breaks for 20 seconds. What is the average force supplied by the breaks to stop the vehicle?

Answers

Write "brake", and "braking" when stopping a car.

m=2500 kg
vi=25 m/s
vf=0
t=20 s

vf=vi+aΔt
0=25+a(20)
solve to get
a=-25/20=-5/4=-1.25 m/s²

Use Newton's second law to get force
force, f = ma
=2500 (-1.25) N
=-3125 N

Ignore the negative sign if understood to be braking force.

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