Question

a car of mass 1200kg traveling at 10m/s collides with a stationary car of mass 1000kg.if the car lock together, calculate the combine speed

Answer 1

From the conservation of momentum:

$$m_1v=(m_1+m_2)u$$

$$(1200)10=(1200+1000)u$$

$$u=5.45\frac{m}{s}$$