Question

A $20kg$ block is placed on top of $50kg$ block as shown in the figure. A horizontal force $F$ acting on A produces an acceleration of $3m/s^2$ in A and $2m/s^2$ in B as shown in the figure. For this situation, choose the correction option(s).

• A. The friction force between A and B is $40N$.
• B. The net force acting on A is $150N$.
• C. The value of $F$ is $190N$.
• D. The value of $F$ is $150N$.

Answer 1

Answer: (A), (B), (C)

The correct options are
A The friction force between A and B is $40N$.
B The net force acting on A is $150N$.
C The value of $F$ is $190N$.


Using the FBD of the block B,
Friction force on block B, $f=m_B{a}_B=20\times 2=40N$
Using the FBD of the block A,
$F-f=m_A{a}_A=50\times 3=150N$
$F=150+40=190N$