Consider a constant force acting on a body that is moving with constant speed

PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power

Problem

Consider a constant force

\mathbf F

acting on a body that is moving with constant speed

v

. The angle between the directions of

\mathbf F

and the velocity is

\theta

. (i) Explain qualitatively how the instantaneous power delivered by the force depends on the angle

\theta

. (ii) If

|\mathbf F|=60\,\text{N}

and

v=2.5\,\text{m\,s}^{-1}

, find the value of

\theta

for which the power delivered is

40\%

of the maximum possible value for the given magnitudes of force and velocity.