Question

Consider a porter standing on a platform with a suitcase which presses his head with a force of 200 N. If this force is taken to be action, then the reaction force is exerted by:

• A. The earth on the suitcase.
• B. The suitcase on the earth.
• C. The earth on the porter.
• D. The head on the suitcase.

Answer 1

The correct option is D The head on the suitcase.

When the suitcase is pressing the person's head, it is acting a force on his head. As stated by Newton's Third Law of motion, if there is a force, there must be an equal and opposite reaction force. Therefore, the reaction force is applied by the head on the suitcase.