Contents
Inertia Makes the Body Resist Changes in Velocity
According to Newton's First Law, an object tends to maintain its current state.
When a car is stationary and suddenly accelerates, your body still tends to remain at rest. The car seat pushes your back forward, while the rest of your body has not yet had time to change its velocity, creating the sensation that a force is pulling you backward.
Conversely, when the car is moving and brakes sharply, the body still wants to continue moving at its previous speed. The car decelerates, but you continue to rush forward due to inertia, making you feel as though you are being pushed forcefully forward.
Body Parts Do Not Move at the Same Time
The human body is not a single, uniform rigid solid.
When a vehicle changes velocity, force acts directly only on the parts in contact with it, such as your feet, the seat, or the seatbelt. Meanwhile, the head, muscles, and internal organs tend to continue moving in their initial state for a very brief moment.
This difference in motion creates internal tension within the body. The brain registers these signals and interprets them as a "sinking feeling" or the sensation of "being jerked."
The Inner Ear Helps You Sense Changes in Velocity
Besides inertia, the vestibular system located in the inner ear also plays an important role.
Inside the inner ear are semicircular canals containing fluid and microscopic motion-sensing cells. When velocity changes abruptly, this fluid cannot move in sync with the body immediately; instead, it continues to shift due to inertia.
That displacement stimulates the sensory cells, sending signals to the brain that the body is accelerating, decelerating, or changing direction. It is this process that creates the sensation of being pulled, swaying, or sometimes dizzy.
That is why even a split-second change in velocity is enough to make you feel as though an invisible force is pulling your body in a particular direction.
Further reading
Image: Dextar Studio - Unsplash
