A particle of mass 0.8 kg moving at 4 m/s rebounds of a wall with coefficient of restitution 0.3. How much Kinetic energy is lost?

Coefficient of Restitution (CoR): Speed of Approach x CoR = Speed of Seperation 4 x 0.3 = 1.2 ms^-1 Kinetic Energy (KE) Lost: KE lost = Initial KE - Final KE Initial KE = 1/2mv²        = 1/2 x 0.8 x 4²        = 6.4 J Final KE = 1/2mv²        = 1/2 x 0.8 x 1.2²        = 0.576 J KE lost = 6.4 - 0.576 KE lost = 5.824 J