Question

During a collision with a truck, a 1500 kg car travelling at 12 m/s comes to a stop in a distance of 1.2 m from the point of collision. (a) what force is exerted on the car by the truck? luckily, the driver of the car is wearing his seat belt and so he slows down at the same rate as the car. (b) what force does the seat belt exert on the driver if his mass is 75 kg?

Answer 1

Answer:

m = 1500 kg

u = 12m/s

v = 0  

s = 1.2m

By Third Equation of Motion

2as = v^2 - u^2

2.4a = -144

a = -1440/24 = -60m/s^2

According to Newton's third Law of Motion

Force exerted by truck on car = Force exerted by car on truck in the opposite direction

Force exerted by truck on car = - ma ( Second Law of Motion ) = - {1500*(-60)} = 90000 N

b)  m = 75kg

a = - 60m/s^2

F = ma (  Second Law of Motion) = 75*(-60) = -4500 N