Question

A truck of mass 15 tons moving with $1$ ms${}^{-1}$ collides with a stationary truck of mass 10 tons and automatically connected to move together. loss of K.E during collision is

• A. 4500 J
• B. 7500 J
• C. 3000 J
• D. 0 J

Answer 1

Answer: (C)

3000 J

Using momentum conservation $v=0.6$ms${}^{-1}$
Initial KE $=0.5\times 15000\times 1=7500$ J
Final KE $=0.5\times 25000\times 36/100=4500$ J
Loss $=3000$ J