# Kinetic Energy Formula

Kinetic Energy Formula

The Kinetic energy is the energy that an object has due to its motion. Ek, is the energy of a mass, m, in motion, v2.

Ek = 1/2 mv2

Ek = Kinetic energy

m = mass

v = velocity

Kinetic Energy Formula Questions.

1) The mass of a baby elephant is 113 kg, and it walks at a constant velocity of 0.5 m/sec. What is the kinetic energy for the baby elephant?

Answer: The mass, m = 113 kg, and the velocity, v = 0.5 m/sec. Use the kinetic energy equation.

Ek = 1/2 mv2

Ek = 1/2 (113 kg) (0.5 m/sec)2

Ek = 1/2 (113 kg)(0.25 m2/s2)

Ek = 14.125 kg m2/sec2 = 14.125 Joules

 If the kinetic energy of a car is 320,000 Joules (3.2 x 105 J), and it's velocity is 25 m/s, what is the vehicle's mass?

Answer: The kinetic energy for the car in motion is Ek = 320,000 J = 32,000 kg m2/s2. The velocity of the car, v = 25 m/s.

Ek = 1/2 mv2

Ek/0.5v2 = m

m = (320,000 kg m2/s2)/[0.5(25 m/s)2]

m = (320,000 kg m2/s2/[(0.5)(625)m2/s2]

m = (320,000 kg m2/s2/312.5 m2/s2

m = 1024 kg

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