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
[2] 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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