Question

1. In a ramp experiment, a trolley of mass 0.5 kg is pushed at a velocity of 0.3m/s. It collides with a second stationary trolley of mass 1.0kg and sticks to it. After collision, both trolleys move off with a velocity of 0.1m/s. Has momentum been conserved?

Answer 1

According to the law of conservation of momentum, we have:

$$p_i=p_f,$$ $$m_1v_{1,i}+m_2v_{2,i}=(m_1+m_2)v_f,$$ $$0.5\ kg\cdot0.3\ \dfrac{m}{s}+0=(0.5\ kg+1\ kg)\cdot0.1\ \dfrac{m}{s},$$ $$0.15\ \dfrac{kg\cdot m}{s}=0.15\ \dfrac{kg\cdot m}{s}.$$

Therefore, momentum has been conserved.