Question

You are riding in the car with your grandfather, and he turns left. Why do you shift to the right?It takes you a moment to catch up with the new velocity of the car.You have more inertia than the car, so it takes longer for you to turn left.You had been sitting at rest until the force of the turn set you in motion.The car continued in the same velocity, but you had a different inertia.

Answer 1

The first statement is essentially right: inertia. Before the turn you and the car were moving together in a straight line. When the car turns left, the car (via the tires, seat, seatbelt, etc.) exerts a leftward force to change its motion. Your body tends to keep going straight (Newton’s 1st law) so, relative to the car, you appear to shift to the right until those contact forces accelerate you left.

In the car’s rotating (non‑inertial) frame this shows up as a fictitious “centrifugal” force pushing you outward to the right. It’s not because you have more inertia than the car or because you were truly at rest—both you and the car had the same initial velocity; your velocity just doesn’t change as quickly as the car’s.