A skier of mass 50 kg is moving at speed 10 m/s at point P₁ down a ski slope with negligible friction. What is the skier's kinetic energy when she is at point P₂, 20 m below P₁? A) 2500 J B) 9800 J C) 12300 J D) 13100 J E) 15000 J

Question

Quizplus · Accepted Answer

The kinetic energy (KE) of an object of mass m moving with velocity v can be calculated by the formula: KE = 0.5 * m * v^2 At point P₁, the skier's kinetic energy is: KE1 = 0.5 * 50 kg * (10 m/s)^2 = 2500 J At point P₂, the skier has lost gravitational potential energy (GPE) and gained an equal amount of kinetic energy due to the conservation of energy. The change in GPE is: ΔGPE = mgh = 50 kg * 9.8 m/s^2 * 20 m = 9800 J Therefore, the skier's kinetic energy at point P₂ is: KE2 = KE1 + ΔGPE = 2500 J + 9800 J = 12300 J Therefore, the best choice is C.

A Skier of Mass 50 Kg Is Moving at Speed