Question

Which statements about braking a car are true?

The greater the kinetic energy of a car, the longer it takes for the car to stop.
The lower the kinetic energy of a car, the longer it takes for the car to stop.
If the speed of a car doubles, the car’s kinetic energy and braking distance quadruple.
If the speed of a car doubles, the car’s kinetic energy and braking distance remain the same.

Answer 1

The greater the kinetic energy of a car, the longer it takes for the car to stop.

If the speed of a car doubles, the car’s kinetic energy and braking distance quadruple.

Step-by-step explanation:

The kinetic energy is given by the formula,

½ mv²

where m is the mass and v is the velocity.

So when the velocity or speed doubles the kinetic energy will quadruple.

A car moving with high kinetic energy has a high speed or velocity therefore it is going to take more time to reduce the higher speed and bring the car to a halt.

Answer 2

Answer: C. If the speed of a car doubles, the car’s kinetic energy and braking distance quadruple. And A.The greater the kinetic energy of a car, the longer it takes for the car to stop.