Question

A 1700 kg car runs into the rear of a stopped car that has a mass of 2500 kg immediately after the collision the cars are hooked together and have a velocity of 3 m/s what was the velocity of car one just before the collision

Answer 1

Given that the mass of car one is m1 = 1700 kg

The mass of car two is m2 = 2500 kg

The initial velocity of car two is

$v_o2=0\text{ m/s}$

The final velocity of both the cars after the collision is

$v_f=\text{ 3 m/s}$

We have to find the initial velocity of car one.

According to the law of conservation of momentum

$m1v_01+m2v_o2=(m1+m2)v_f$

Substituting the values, the initial velocity of the car will be

$\begin{gathered} 1700(v_01)+2500\times0=(1700+2500)\times3 \\ v_01=7.412\text{ m/s} \end{gathered}$

Thus the initial velocity of the car one is 7.412 m/s.