PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A small block of mass m rests on a horizontal, frictionless table. A constant horizontal force of magnitude F is applied to the block starting at t=0. The force remains constant for several seconds.
(a) Describe qualitatively how the speed of the block varies with time while the force is applied.
(b) Explain how the instantaneous power delivered to the block by the force depends on time. Your explanation should explicitly connect the time-dependence of speed to the time-dependence of power.
(c) On clearly labeled axes, sketch the expected graph of instantaneous power P versus time t for the interval during which the force is applied. No numerical values are required.
(d) Identify what physical quantity is represented by the area under the P–versus–t graph between two arbitrary instants t1 and t2, and justify your answer.