a motor car of mass 800kg travelling at 20m/s is brought to rest by breakes in 100m.calculate the average breaking force required.in physics

Answer 1

Use kinematics equation:
v1²-v0²=2aS

v1=final velocity (0 m/s)
v0=initial velocity (20 m/s)
S=distance travelled (100 m)
solve for
a=acceleration (negative because it's a deceleration)

Use Newton's second law
F=ma
m=mass
F=average (uniform) force over the deceleration.

Answer 2

using V2=U2+2aS
a=V2_U2/2S=20*20/2*100=400/200=2m/s2

F= ma
F=800*2=1600N

Answer 3

Is the answer correct

Answer 4

Good