Question

A footballer kicks a football of mass 430 g and it flies off at a speed of 8 m/s. What is the KE of the football?

Answer 1

Answer:

13.76 Joules

Explanation:

The SI units for joules are defined to be kilogram*meters per second. Therefore, we must turn the grams to kilograms by dividing the answer by 1,000. This is due to 1,000 grams being in a single kilogram. Kinetic energy is defined to be:

$KE=\frac{1}{2} mv^2$

Therefore:

$KE=\frac{1}{2} (0.43kg)(8m/s)^2=13.76J$