Question

A 2 kg mass moving with a velocity of $10m{s}^{-1}$ collides with another 6 kg mass moving in opposite direction with a velocity of $20m{s}^{-1}$. After the collision, they stick and move together. Find their common velocity and the momentum.

• A. $12.5m/s,100kgm{s}^{-1}$
• B. $12.5m/s,50kgm{s}^{-1}$
• C. $7.5m/s,100kgm{s}^{-1}$
• D. $7.5m/s,50kgm{s}^{-1}$

Answer 1

The correct option is A

$12.5m/s,100kgm{s}^{-1}$

$m_1{u}_1+m_2{u}_2=m_1{v}_1+m_2{v}_2\left(2\right)\left(10\right)-\left(6\right)\left(20\right)=\left(8\right)v\Rightarrow v=\frac{100}{8}m/s=12.5m/sp=8v=100m/s$