Which has greater kinetic energy, a car traveling at 30 km/h or another car of half the mass traveling at 60 km/h?

Question

Quizplus · Accepted Answer

The kinetic energy of an object is directly proportional to its mass and the square of its velocity.

Therefore, the kinetic energy of the car traveling at 30 km/h would be:

KE1 = (1/2)mv1^2

And the kinetic energy of the car traveling at 60 km/h would be:

KE2 = (1/2)(1/2)m(v2^2)

Where m is the mass of the car, v1 is the velocity of the first car (30 km/h), and v2 is the velocity of the second car (60 km/h).

Since the second car has only half the mass of the first car, the kinetic energy of the second car is still greater despite having half the velocity of the first car.

Thus, the car traveling at 60 km/h has greater kinetic energy than the car traveling at 30 km/h.

Which Has Greater Kinetic Energy, a Car Traveling at 30