Question

A body of mass 4 kg moving with velocity 12 m/s collides with another body of mass 6 kg at rest. If two bodies stick together after collision, then the loss of kinetic energy of system is

• A. Zero
• B. 288 J
• C. 172.8 J
• D. 144 J

Answer 1

Answer: (C)

172.8 J

Answer 2

Loss in K.E. = $\frac { m _ { 1 } m _ { 2 } } { 2 \left( m _ { 1 } + m _ { 2 } \right) } \left( u _ { 1 } - u _ { 2 } \right) ^ { 2 }$

= $\frac { 4 \times 6 } { 2 \times 10 } \times ( 12 - 0 ) ^ { 2 }$= 172.8 J