# Average Kinetic Energy of 2 Objects

If I had 2 objects of equal mass ( 10kg for example ), and knew that the average speed of the 2 objects was 8 ms-1 , is it possible to calculate the average kinetic energy of the 2 objects. I attempted the speed of object 1 to be 6 ms-1 and the speed of Object 2 to be 10 ms-1 . So the average kinetic energy would be (180 + 500)/2 = 340 Joules , however that is not equal to 320 when you use the average speed so 1/2 * 10 * 82. I understand about root mean squared, but if you don't know the initial values of the speed but only the average is it just not possible to calculate average kinetic energy?

## 2 Answers By Expert Tutors

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Frank C. answered • 12/21/19

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Frank C.

Here's an example of similar logic. If you had two objects of same mass traveling at equal speeds in opposite directions, their average velocity would be zero. If you used that to calculate kinetic energy, you'd get zero! But that is certainly not the kinetic energy of either object on its own; their kinetic energies are both non-zero and positive.
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12/21/19

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