Question

A car of mass 1394 kg collides head-on with a parked truck of mass 2000 kg. Spring mounted bumpers ensure that the collision is essentially elastic. If the velocity of the truck is 17 km/h (in the same direction as the car's initial velocity) after the collision, what was the initial speed of the car?

Answer 1

Answer:

V = 20.69 km/h

Explanation:

given data

mass car = 1394 kg

mass truck = 2000 kg

velocity of the truck = 17 km/h

solution

we know that here

m1 v = m1 v1 + m2 v2   ..................... 1

so here

0.5 × m1 × v1i² = 0.5 × m × v1f² × + 0.5 × m2 × v2f²

put here value and we get truck initial velocity

v2f =  $\frac{2m1v1}{m1+m2}$    

put here value

17 = $\frac{2\times 1394\times V}{1394+2000}$

V = $\frac{1697}{82}$  

V = 20.69 km/h