Problem 8-75 Inelastic collision - Part 4 - A

Two trucks have a completely inelastic collision. After the collision, they have a common velocity of \(11 \;m/s\) at \(35^\circ\) south of west. Before the collision, one truck \((\text{mass} \; 2.3\times10^4\; kg)\) has a velocity of \(15\; m/s\) at \(51^\circ\) south of west. Determine the initial velocity (magnitude and direction) of the other truck \((\text{mass} \; 1.2\times10^4\; kg).\)

Accumulated Solution

FBD with illustration of before and after

\(v_{1x} = (-15) \cos 51 \\ v_{2x} = v_2 \cos \theta \\ v_x{'} = (-11) \cos 35\)

Correct.

What is the correct expression for conservation of momentum in the \(x\) direction?

(A)   \(v_{1x} + v_{2x} = v_x{'}\)

(B)   \(m_1v_{1x} + m_2v_{2x} = (m_1 + m_2)v_x{'}\)

(C)   \((1/2)m_1v_{1x}{^2} + (1/2)m_2v_{2x}{^2} = (1/2)(m_1 + m_2)v{_x}^{'2}\)