PhysicsThree blocks A, B and C , of masses 4 kg , 2kg and 1kg respectively, are in contact on a frictionless surface, as shown. If a force of 14 N is applied on the 4kg block, then the contact force between A and B is

Three blocks A, B and C , of masses 4 kg , 2kg and 1kg respectively, are in contact on a frictionless surface, as shown. If a force of 14 N is applied on the 4kg block, then the contact force between A and B is

A
2N
B
6N
C
8N
D
18N

Solution:

Here m₁=3 kg, m₂=2kg, m₃=1 kg

Acceleration of system
$a = \frac{F}{m_{1} + m_{2} + m_{3}} = \frac{14}{4 + 2 + 1} = 2 {ms}^{- 2}$
Contact force between A and B
$= (m_{2} + m_{3}) a = (2 + 1) \times 2 = 6 N$