Question

A constant force $\overrightarrow{F}$ is acting on a body of mass m with constant velocity $\overrightarrow{v}$ as shown in the figure the power P exerted is

• A. $Fv\cos \theta$
• B. $\frac{F\cos \theta }{mg}$
• C. $\frac{Fmg\cos \theta }{v}$
• D. $\frac{mg\sin \theta }{F}$

Answer 1

The correct option is A $Fv\cos \theta$

From the diagram,

the horizontal component of force is, $F_x=Fcos\theta$

The vertical component of force, $F_y=Fsin\theta =mg$

Power, $P=\overrightarrow{F}.\overrightarrow{v}$

$P=Fvcos\theta$

The correct option is A.