An athlete with a mass of $57\mathrm{.}0$ kg is in a cross country race, and at one instant he has a speed of $5\mathrm{.}30$ m$/$s$.$

$($a$)$

What is his kinetic energy at this instant?

KEi $=$ J

$($b$)$

If he wishes to doubles his speed to reach the finish line, his kinetic energy will change by what factor?

KEf$/$KEi

$=$