When both the weight and speed of a vehicle are doubled, what is the effect on stopping power?

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

Answer: (D)

When both the weight and speed of a vehicle are doubled, the stopping power is affected significantly due to the physics involved in stopping a vehicle. Stopping power is not only dependent on the braking force but also on the kinetic energy of the vehicle, which is influenced by both its weight and speed.

The kinetic energy (KE) of a vehicle is calculated using the formula KE = 1/2 * mass * velocity². If the weight (mass) of the vehicle is doubled, that contributes directly to an increase in the kinetic energy. Simultaneously, if the speed is also doubled, the impact on kinetic energy is even more pronounced. Since kinetic energy increases with the square of the velocity, doubling the speed causes the kinetic energy to increase by a factor of four (2²).

Therefore, when both factors are applied: doubling the weight (mass) contributes to an increase in kinetic energy by a factor of two, and doubling the speed contributes to an increase by a factor of four. The total increase in kinetic energy is given by multiplying these effects together:

2 (from doubling mass) * 4 (from doubling speed) = 8.

Consequently, the effect on stopping power, which is the ability to bring a vehicle