Question

question 10 of 28 freya has a mass of 14 kg. she is running at 1.1 m/s to the left when she runs into eric, who is standing still. eric has a mass of 18 kg. after the collision, they continue moving together. what is their velocity after the collision? a. 1.4 m/s to the left b. 0.48 m/s to the left c. 0.86 m/s to the left d. 2.5 m/s to the left

Explanation:

Step1: Define variables

$m_1=14\ \text{kg}, v_1=1.1\ \text{m/s (left)}, m_2=18\ \text{kg}, v_2=0\ \text{m/s}$

Step2: Initial momentum

$p_{\text{initial}}=m_1v_1 + m_2v_2=14\times1.1 + 18\times0=15.4\ \text{kg·m/s}$

Step3: Combined mass

$m_{\text{total}}=m_1 + m_2=14 + 18=32\ \text{kg}$

Step4: Final velocity

$p_{\text{initial}}=m_{\text{total}}v_{\text{final}} \implies v_{\text{final}}=\frac{15.4}{32}\approx0.48\ \text{m/s (left)}$

Answer:

B. 0.48 m/s to the left