A small hovercraft starts from rest on a frictionless lake
PHYSICS · Single correct · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A small hovercraft starts from rest on a frictionless lake. Its motor supplies constant mechanical power after ignition. Which statement best describes how the magnitude of the hovercraft’s acceleration changes as time progresses?
(a) Its acceleration remains constant, because the motor’s power output is constant.
(b) Its acceleration decreases in inverse proportion to time, a∝1/t, since the craft must share the same power with ever-greater kinetic energy.
(c) Its acceleration decreases with time because the same power must accelerate a craft that is moving faster and faster.
(d) Its acceleration increases proportionally to t as the craft gains speed.