Question

What do you think would make more difference in a car’s energy of motion: doubling its mass or doubling its speed?

Answer 1

In fact, kinetic energy is directly proportional to mass: if you double the mass, then you double the kinetic energy. ... A car moving 40 mph has four times as much kinetic energy as one moving 20 mph, while at 60 mph a car carries nine times as much kinetic energy as at 20 mph..