If you double the speed of a car, you increase its force of impact __________ times.

Doubling the speed of a car increases its force of impact by four times. This principle arises from the physics of kinetic energy, which is expressed by the formula: kinetic energy = 1/2 mv², where 'm' is mass and 'v' is velocity.

When the speed of the car (velocity) is doubled, the new kinetic energy becomes 1/2 m(2v)². Simplifying this gives us 1/2 m(4v²), which means the kinetic energy—and thus the force of impact—becomes four times greater than it was at the original speed. This increase is due to the square of the velocity in the kinetic energy formula, illustrating how speed dramatically affects the impact force during a collision.