Question

A car of mass 10 metric ton rolls at $2m{s}^{-1}$ along a level track and collides with a loaded car of mass 20 metric ton, standing at rest. If the cars couple together, loss in K.E during collision is

• A. $1KJ$
• B. $1.33J$
• C. $1.33KJ$
• D. $1.33\times {10}^4$J

Answer 1

Answer: (D)

$1.33\times {10}^4$J

$FinalK.E.=\frac{1}{2}\times 30\times {\left(\frac{2}{3}\right)}^2\times {10}^3$

$InitialK.E.=\frac{1}{2}\times 10\times 2^2\times {10}^3$

$\Delta K.E=(6.67-20)\times {10}^3$
$=-1.3\times {10}^{4}J$