Calculation of Kinetic Energy

Question: If a rock has a mass of 1 kg and is thrown at 5 m / s, what is its kinetic energy?

Answer:

Step 1: Analyze the question to determine what information is provided

• The mass of the rock
  
• The speed of the rock
  

These are both in the correct units so we do not have to worry about unit conversions.

Step 2: Analyze the question to determine what is being asked

• We are asked to find the kinetic energy. From the definition we know that to work out E _k, we need to know the mass and the velocity of the object and we are given both of these values.

Step 3: Substitute and calculate the kinetic energy

To check that the units in the above example are in fact correct:

The units are indeed correct!