Question

A 801 kg car stopped at an intersection is rear-ended by a 1550 kg truck moving with a speed of 16.0 m/s. If the car was in neutral and its brakes were off, so that the collision is approximately elastic, find the final speed of both vehicles after the collision. m/s (car) m/s (truck)

Answer 1

Given is:-

mass of the car m₁ = 801kg

Initial speed of the car u₁ = 0 m/s

mass of the truck m₂ = 1550kg

Initial speed of the truck u₂ = 16 m/s

Now,

Applying conservation of momentum we get

eq-1

And by applying conservation of kinetic energy we get

eq-2

From eq-1 and eq-2

we get

eq-3

and

eq-4

BY plugging values in eq-3 we get the final speed of the car which is

and the final speed of the truck is

Hence the final speed of both the vehicles after the collision are

car= 21.1m/s

and

truck = 5.1m/s