Question

A car is pulled with a force of 10,000 N. The car's mass is 1267 kg. But, the car covers 394.6 m in 15 seconds

Answer 1

F=m*a=>a=F/m=10000/1267=7.89 m/s²

d=v₀t+a't²/2<=>394.6=112.5*a'=>a'=3.5

a-a'=7.89-3.5=4.39 m/s²

This difference causes friction forces

We apply the second principle of dynamics: vector: F + N + G + Ff = ma (vector vectors, I can not here)

Scalar: Ox: F-Ff = ma

            Oy N-mg = 0

Ff = -ma+ F =-1267*7.89+10000=-8869+10000=1131 N

This frictional force (Ff) is opposite to the traction (F)