An ice skater of a mass of 50kg is initially moving at 5m/s, before decreasing their kinetic energy by 75J. Calculate their final speed.

4.69 m/s

Explanation:

The formulae for calculating Kinetic Energy (K. E) is;

K. E = 0.5 * m * v² where

m - mass (kg)

v - velocity (m/s)

The initial K. E by the ice skater is, therefore;

= 0.5 * 50 * 5²

= 625 joules

The ice skate loses 75 joules so they are left with K. E of;

625 - 75

= 550 joules

Since their mass does not change, their velocity changes to;

550 = 0.5 * 50 * v²

22 = v²

v = 4.69

= 4.69 m/s