Question

The total masses of BlueCart and RedCart (including its mass) are 240g and 350g respectively. The velocities of BlueCart and RedCart before collision are +0.543 m/s and -0.441 m/s respectively while the velocities after collision are -0.559 m/s and +0.321 m/s. What is the total momentum before collision?

Answer 1

The total momentum before collision is

$$p_i=m_1v_1+m_2v_2,\\ p_i=0.24·0.543+0.35(-0.441)=-0.024\text{ kg-m/s}.$$