Question

In the given figure, acceleration of 4 kg block is
(Take $g=10m/s^2$)

• A. 3 m/$s^2$
• B. 2.5 m/$s^2$
• C. 2 m/$s^2$
• D. 3.5 m/$s^2$

Answer 1

The correct option is B 2.5 m/$s^2$

Maximum frictional force experienced by block of 2 kg = $\mu$N = $\mu$mg = $0.8\times 2\times 10$ = 16 N.
Since the force applied is less than maximum frictional force, hence both the blocks move together.
By F =15 N, acceleration is
$a=\frac{F}{m_1+m_2}$
$=\frac{15}{2+4}$
$=2.5m/s^2$