Question

The dot product of force and velocity is called:

• A. work
• B. power
• C. energy
• D. momentum

Answer 1

The correct option is B

power

The explanation of the correct option

In case of option B:

Force times velocity can also be written as force times displacement over time

$\overrightarrow{F}·\overrightarrow{v}=\overrightarrow{F}·\frac{\overrightarrow{d}}{t}......\left(i\right)[where\overrightarrow{F}=force,\overrightarrow{d}=displacement,t=timetaken]$

We know force times displacement is equal to work. Now, $\overrightarrow{F}·\overrightarrow{d}=\overrightarrow{W}$

Now on putting in equation (i) we will get, $\overrightarrow{F}·\frac{\overrightarrow{d}}{t}=\frac{W}{t}$

Work divided by time is equal to the power $\frac{W}{t}=p$

Therefore the dot product of force and velocity is power.

Hence, option (B) is the correct answer.

The explanation of the incorrect options:

In case of option A:

Work is the dot product of force and displacement. Hence it is an incorrect option.

In case of option C:

The energy stored in an object due to its position and height is known as potential energy and is given by the formula: $P.E.=mgh[m=mass,h=height,g=accelerationduetogravity]$

In case of option D:

Momentum is the dot product of mass and velocity. Hence it is an incorrect option.