Question

Three identical blocks each of mass $M$ are along a frictionless table and a force $F$ is acting as shown. Which of the following statement is false?

• A. The net vertical force on block A is zero
• B. The net force on block A is $\frac{F}{3}$
• C. The acceleration of block C is $\frac{F}{3 M}$
• D. The force of interaction between A and B is $\frac{F}{3}$

Answer 1

Answer: (D)

The acceleration of the system in rightward direction is
$a=\frac{F}{m_{A} + m_{B} + m_{C}}=\frac{F}{3 M}$
For A
From force diagram of A, the Net force on A $=F-F_{1}$
$=m_{1}a=\frac{M F}{3 M}=\frac{F}{3}$


The force interaction between A and B is $F_{1}=F-\frac{F}{3}=\frac{2 F}{3}$