Question

Two blocks 'A' and 'B' each of mass 'm' are placed on a smooth horizontal surface. Two horizontal force F and 2F are applied on the 2 blocks 'A' and 'B' respectively as shown in figure. The block A does not slide on block B. Then the normal reaction acting between the two blocks is –

• A. F
• B. $\frac{F}{2}$
• C. $\frac{F}{\sqrt{3}}$
• D. 3F

Answer 1

Answer: (D)

3F

Answer 2

Acceleration of two mass system is a = $\frac{F}{2m}$ leftward

FBD of block A

N cos 60⁰ – F = ma = $\frac{mF}{2m}$ solving N = 3F