Question

A small block of a mass m = 1 kg is placed over a wedge of mass M = 4 kg as shown in the figure. Mass ‘m’ is released from rest. All surfaces are smooth. Origin ‘O’ is as shown in the figure.

Normal reaction between the two blocks at an instant when absolute acceleration of ‘m’ is $5\sqrt{3}m/s^2$ (at an angle ${60}^{\circ }$ with the horizontal) is ___N. Consider that the normal reaction at the instant is making ${30}^{\circ }$ with the horizontal.

• A. 6
• B. 10
• C. 4
• D. 5

Answer 1

The correct option is D

5

$\left(F_{net}\right)x=N_{1}cos{30}^{\circ }=m{a}_{x}or,N_1=\frac{m{a}_x}{cos{30}^{\circ }}=\frac{1\times 5\sqrt{3}\times \left(\frac{1}{2}\right)}{\frac{\sqrt{3}}{2}}=5N$​