Question

A bicyclist goes from a speed of 5 m/s to a speed of 10 m/s. What happens to her kinetic energy?

Answer 1

Answer:

C

Explanation:

The kinetic energy of an object can be calculated via the following equation:

$k = \frac{1}{2} m {u}^{2}$

where:

K : kinetic energy

m: mass of the object

v: its velocity

when the speed changes, the kinetic energy changes as well. Lets suppose that it doubles, as on the problem stated. Then K is increased by a factor of four. in other words...

$newk = \frac{1}{2} m {(newu)}^{2} = \frac{1}{2} m {(2u)}^{2} \\ = \frac{1}{2} m(4 {u}^{2} ) = 4( \frac{1}{2} m {u}^{2} ) = 4k$