Question

Determine the time in which the smaller block reaches the other end of block (size of the small block is negligible)

• A. 4 s
• B. 8 s
• C. 2.19 s
• D. 2.31 s

Answer 1

The correct option is C

2.19 s

$\text{Friction force between 2kg and 8 kg}f=0.3\times 2\times 10=6N\text{for 2kg block}10-6=2a_1{a}_1=2m/s^2\text{for 8kg block}6=8a_2{a}_2=\frac{3}{4}m/s^2{a}_{rd}=a_1-a_2=\frac{5}{4}m/s^2\text{using equation of motion}3=\frac{1}{2}\times \frac{5}{4}\times t^{2}t=2.19s$