Doubling which of the following increases the kinetic energy of a body the most?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Its speed
Kinetic energy is \(\frac{1}{2}mv^{2}\): it is proportional to the mass but to the square of the speed.
Doubling the mass doubles the kinetic energy
Doubling the weight (\(mg\)) means doubling the mass, so the kinetic energy again doubles
Doubling the density of a body of the same size doubles its mass, so the kinetic energy doubles
Doubling the speed makes \(v^{2}\) four times as large, so the kinetic energy becomes four times as large