Answer:
45 N
Step-by-step explanation:
When you push on a wall with a force of 45 N, the wall applies an equal and opposite force back to you, according to Newton's third law of motion. This is known as the action-reaction pair of forces. So, the force that the wall applies back to you is also 45 N.
To understand this concept, imagine pushing a wall with your hand. As you apply a force to the wall, your hand feels the resistance from the wall pushing back with an equal amount of force. This is because forces always occur in pairs - for every action, there is an equal and opposite reaction.
Therefore, the correct answer is 45 N. The wall applies a force of 45 N back to you in response to your 45 N push.