Suppose a moving object has a kinetic energy of 100 J. What will the object's kinetic

energy be if it's speed is doubled

400J

Explanation:

K. E = 1/2mv^2

If the speed is doubled, then it becomes:

K. E (2) = 1/2 (m2v) ^2

K. E (2) = 1/2m4v^2

K. E (2) = m2v^2

K. E (2) / K. E = (1/2mv^2) / (m2v^2)

K. E (2) / K. E = 1/4

Therefore, K. E (2) = 4K. E

When k. E=100j

K. E (2) = 4 * 100 = 400J