A car of mass 1200kg travelling @ 72 km/h is brought to rest in 4s.Find a) the average deceleration b)the average braking force

Answer 1

a) 72 km/h = 20 m/s
Deceleration = 20/4 = 5 m/s^2

b) Momentum change = Avg. Force * Time
Solve for the Average Force

Answer 2

a) Deceleration is -5

b) Average braking force -6000

Answer 3

15000N

Answer 4

A 5m\s B 6000

Answer 5

Deceleration =5m/s^2
Force=6000N

Answer 6

72km/h=20m/s
20/4
=5m/s