Practice Test 4

A stationary $5.0,\text{kg}$ object explodes into $1.0,\text{kg}$ and $4.0,\text{kg}$ fragments; the $1.0,\text{kg}$ fragment moves $+20,\text{m/s}$. Determine the $4.0,\text{kg}$ fragment velocity.

Two cars stick together: $m_1=1000,\text{kg}$ at $+25,\text{m/s}$, $m_2=1500,\text{kg}$ at $+5,\text{m/s}$. What is the final velocity?