Question

Collision practice

Answer 1

Answer:

$v_f=4\:\mathrm{m/s\: in\:Biff's\:direction}$

Explanation:

Using the Law of Conservation of Momentum, we can set up the following equation:

$m_2v_2-m_1v_1=m_fv_f$, where $m_1v_1$ is Bruce's momentum and $m_2v_2$.

Plugging in given values, we get:

$90\cdot7-45\cdot2=(90+45)v_f, \\v_f=\frac{540}{135}=\fbox{ 4\:\mathrm{m/s} }$.