Which formula gives kinetic energy?

Which formula gives kinetic energy?

• A. KE = m g h
• B. KE = P t
• C. KE = V I
• D. KE = 1/2 m v^2

Answer: (D)

Kinetic energy is the energy of motion. For an object with mass m moving at speed v, the energy of motion is KE = 1/2 m v^2. The square of the speed shows why faster motion requires disproportionately more energy, and the 1/2 comes from the work needed to accelerate from rest. The units work out to joules (kg·m^2/s^2), confirming it as energy. The other expressions describe different ideas: m g h is gravitational potential energy (energy due to height in a gravitational field); P t represents energy transferred over time (power times time), not specifically kinetic energy; V I is electrical power (voltage times current), not the kinetic energy of motion.

Kinetic energy is the energy of motion. For an object with mass m moving at speed v, the energy of motion is KE = 1/2 m v^2. The square of the speed shows why faster motion requires disproportionately more energy, and the 1/2 comes from the work needed to accelerate from rest. The units work out to joules (kg·m^2/s^2), confirming it as energy.

The other expressions describe different ideas: m g h is gravitational potential energy (energy due to height in a gravitational field); P t represents energy transferred over time (power times time), not specifically kinetic energy; V I is electrical power (voltage times current), not the kinetic energy of motion.