Question

A car of mass 1,000 kg, including everything inside it, is moving on a horizontal road with a velocity of 72 km/h. The driver applies the brakes, and the car stops in 4 seconds. Assume that the acceleration prodnced is constant. How much force was applied on the car during this period? which object exerned this

Answer 1

M=1000
U=72*5/18=20m/s
V=o
Acceleration=v-u/t
0-20/4=-5m/s2
We know,force= mass *acceleration
F=1000*-5
=-5000
The negative sign shows that force of friction is applied to the car

Answer 2

Answer:

m=1000, u =72*5/18 =20 and v=0 then a=v-u/t =0-20/4 = -5m/s. f=ma. 1000×(-5)=-5000