Question

Two blocks 'A' and 'B' are in contact on a horizontal surface. A 30 N constant force is
applied to block 'A' as shown below. The magnitude of the force of 'A' on 'B' is
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Answer 1

Solution:

Mass of A = m(A) = 12 kg

Mass of B = m(B) = 33 kg

Total mass of the system = m = 12 + 33 = 45 kg

net force on the system = F = 30 N

net acceleration of the system = a = F/m

=> a = 30/45 = 2/3 m/s^2

acceleration of B = a = 2/3 m/s^2

net force on B = m(B) × a = 33 × 2/3 = 22 N

this 20 N force on B is applied by A .

hence, required force = 20 N ....... answer..