Question

Which statements about braking a car are true? A)The greater the kinetic energy of a car, the longer it takes for the car to stop. B) The lower the kinetic energy of a car, the longer it takes for the car to stop. C)If the speed of a car doubles, the car’s kinetic energy and braking distance quadruple. D)If the speed of a car doubles, the car’s kinetic energy and braking distance remain the same.

Answer 1

Answer:

I believe the correct option is C.

Thank You

Answer 2

Answer:

option c  

Explanation:

Kinetic energy is due to the speed of a body.

$K.E = \frac{1}{2}mv^2$

When speed is doubled, the kinetic energy  is quadruple.

From third equation of motion, braking distance is also proportional to square of speed. Thus, when speed is doubled, the braking distance is quadruple.

Thus, option c is correct.