An object with mass of 2 kg is moving along a horizontal surface with a velocity components vx = 5m/s and vy = - 2.5m/s. What is the objects speed? What is its kinetic energy?

To final the velocity, get the resultant of the given components of velocity,

v = sqrt ((vx) ² + (vy) ²)

v = sqrt ((5 m/s) ² + (-2.5 m/s) ²)

v = 5.59 m/s

The kinetic energy is,

KE = 0.5mv²

Substituting the values,

KE = 0.5 (2 kg) (5.59 m/s) ² = 31.2481 J