Question

In figure shown, both blocks are released from rest. The time to cross each other is:

• A. 2 second
• B. 3 second
• C. 1 second
• D. 4 second

Answer 1

Answer: (C)

$a=\frac{4g-g}{4+1}=\frac{3g}{5}$
$s_{rel}=6m$
$a_{rel}=\frac{6g}{5}=12m/s^2$
$t=\sqrt{\frac{2s_{rel}}{a_{rel}}}=1s$