Question

Three objects A, B and C are kept in a straight line on a friction less horizontal surface. There have masses $m,2m$ and $m$ respectively. The object A moves towards B with a speed $9m/s$ and makes a perfectly inelastic collision with C. All motion occur on same straight line. The final speed of the object C is:

• A. $3m/s$
• B. $4m/s$
• C. $5m/s$
• D. $2.15m/s$

Answer 1

The correct option is D $2.15m/s$

$V_{f_B}^{\to }=\left(\frac{m}{3m}\right)V=\frac{1}{3}\times 9=3\frac{m}{s}{V}_{f_c}^{\to }=\left(\frac{3m}{4m}\right)\left(3\right)=\frac{9}{4}=2.15\frac{m}{s}$