Question

A 1250 kg car is stopped at a traffic light. A 3550 kg truck moving at 8.33 m/s hits the car from behind. If bumpers lock, how fast will the two vehicles move?

Answer 1

the two vehicles will be moving at a speed of 6.16 m/s

Step-by-step explanation:

This is a case of completely inelastic collision, therefore, the conservation of momentum can be written as:

`m_1\,v_1+m_2\,v_2=(m_1+m_2)\,v_f`

which given the information provided results into:

`m_1\,v_1+m_2\,v_2=(m_1+m_2)\,v_f\\(1250)\,(0)+(3550)\,(8.33)=(1250+3550)\,v_f\\29571.5=4800\,v_f\\v_f=6.16\,\,m/s`