In fig. we have two blocks, A and B. The boy pushes block A which lies next to block B

Hence, the boy applies force on block B also.

Now, when the boy pushes block A, the following forces acts –

1. A pair of action-reaction forces between the man and block A.

2. Weight of the man, block A and block B as action forces on the ground in the downward direction.

3. Reaction of the ground on the man, block A and block B in the upward direction to balance their weights.

4. A pair of electromagnetic forces between the blocks B and the Earth.

5. A pair of gravitational forces between the blocks B and the Earth.

6. A pair of gravitational forces between the blocks A and B.

7. A pair of electromagnetic forces between the blocks A and B.