Question

A car of mass 800kg is travelling with a velocity of 18km/h. When breaks are applied it stops after travelling a distance of 25 meters. Find a resitive force(N).
A) 400N B) 300N C) 350N D) 500​

Answer 1

m=800 kg

Vo=18 km/h=5 m/s

V=0 m/s

S=25 m

F-?

F=ma

S=(V²-Vo²)/2a

a=-Vo²/2S

a=-25/2*25=-0.5 m/s²

F=800*0.5=400 N

A