What happens to the stopping power when the speed of a vehicle is doubled?

• A. It remains the same
• B. It doubles
• C. It quadruples
• D. It increases eightfold

Answer: (C)

When the speed of a vehicle is doubled, the stopping power, which is related to the force required to bring the vehicle to a stop, actually increases significantly. This is due to the principles of physics, particularly the relationship between speed, kinetic energy, and the distance needed to stop a vehicle.

Kinetic energy is calculated using the formula ( KE = \frac{1}{2} mv^2 ), where ( m ) is mass and ( v ) is velocity. When the velocity is doubled, the kinetic energy increases by a factor of four, since squaring the velocity means that if you multiply the speed by two, you carry out ( 2^2 = 4 ). This increased kinetic energy means that it will take significantly more force — and hence more stopping power — to bring the vehicle to a complete stop.

To summarize, when the speed of a vehicle is doubled, the stopping power required escalates to four times what it was originally, thus making the correct answer that the stopping power quadruples. This concept is critical for drivers to understand, as it has significant implications for safety and stopping distances at higher speeds.