Question

When you take off in a jet aircraft, there is a sensation of being pushed back into the seat. Explain why you move backward in the seat—is there really a force backward on you? (The same reasoning explains whiplash injuries, in which the head is apparently thrown backward.)

Short answer

When the jet aircraft exerts a force, our body also experiences the same force but in the opposite direction, due to which we are moved backward in the seat.

Step-by-step solution

Concept of Newton’s third law of motion

Newton’s Third Law of Motion tells that whenever a body exerts a force on another body, the first body experiences a force that is equal in magnitude and opposite in direction to the force that it exerts.

Net force acting on a body at the top of the trajectory

The jet aircraft exerts a force to get an upward acceleration. The person sitting in the jet aircraft also experiences the same force and is moved back due to the inertia of the rest of the body. Inertia is the tendency of a body to be in a state of rest or motion with a constant velocity.

When the jet aircraft exerts a force, our body also experiences the same force but in the opposite direction, due to which we are moved backward in the seat.