A rugby ball of mass 0.50 kg is kicked to a speed of 12 m/s. What is its kinetic energy?

Get ready for the NCEA Level 1 Energy Test. Utilize flashcards and multiple choice questions with clear explanations and hints. Prepare for success!

Multiple Choice

A rugby ball of mass 0.50 kg is kicked to a speed of 12 m/s. What is its kinetic energy?

Kinetic energy depends on mass and speed, calculated as KE = 1/2 m v^2. Here m = 0.50 kg and v = 12 m/s. Square the speed: 12^2 = 144. Multiply by the mass: 0.50 × 144 = 72. Take half of that: 72 × 1/2 = 36 J. So the rugby ball has 36 joules of kinetic energy. The 1/2 factor is essential; without it you’d get 72 J, which isn’t correct for this speed and mass. The energy grows with mass and with the speed squared.

Kinetic energy depends on mass and speed, calculated as KE = 1/2 m v^2. Here m = 0.50 kg and v = 12 m/s. Square the speed: 12^2 = 144. Multiply by the mass: 0.50 × 144 = 72. Take half of that: 72 × 1/2 = 36 J. So the rugby ball has 36 joules of kinetic energy. The 1/2 factor is essential; without it you’d get 72 J, which isn’t correct for this speed and mass. The energy grows with mass and with the speed squared.

More practice questions