2024 Laws of MotionNewton's Third Law and Contact Force Medium Question 6 of 72 in Laws of Motion

A horizontal force 10 N is applied to a block A as shown in figure [add image]. The mass of…

A horizontal force 10 N is applied to a block A as shown in figure [add image]. The mass of blocks A and B are 2 kg and 3 kg, respectively. The blocks slide over a frictionless surface. The force exerted by block A on block B is:
A 6 N
B 10 N
C zero
D 4 N

The answer is A.

Solution

Common acceleration $a = \frac{F}{m_A + m_B} = \frac{10}{2 + 3} = 2\ ms^{-2}$ Force exerted by A on B (normal reaction) $= m_B \times a = 3 \times 2 = 6$ N

Concept Contact force between blocks pushed together

Laws of Motion in past papers

72 questions from this chapter have appeared across 27 exam years.