Question

a car of mass 100kg moving with velocity of 45 km/hr collides with a tree and comes to stop in 5 seconds. What will be the force exerted by the car on the tree?

Answer 1

Mass of The Car=100 kg

Intial Velocity (u)Before Striking=45 km/h

In m/s=12.5 m/s

Intial Velocity (u)=12.5 m/s

Final Velocity (v)After Striking=0m/s

Time(t)=5 Seconds.

Find Accerlation.(a)

Use Equation of Motion.

v=u+at

0=12.5+a×5

-12.5=5a

a=-12.5/5

a=-2.5 m/s
____________________
Accerlation=-2.5 m/s

Mass=100 kg

Force=Mass×Accerlation

Force=100×-2.5

Force=-250 N

(N) Is SI unit of Force.

Force Exerted By Car=-250 N

$\boxed{\mathbf{Force=-250\:N}}$