Physics Work & Energy NUMS 2023
PMDC Verified Question 36 of 108
Power is dot product of:
A
Force and displacement
B
Force and velocity
C
Force and time
D
Work and time
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Force and velocity
Concept:

Power is the rate of doing work. By substituting the definition of work into the power equation, we uncover a vector relationship.

Formula:

$$ P = \frac{W}{t} = \frac{\vec{F} \cdot \vec{d}}{t} $$

Solution:

  • Since velocity \( \vec{v} = \frac{\vec{d}}{t} \), we can rewrite the equation.


  • \( P = \vec{F} \cdot \left(\frac{\vec{d}}{t}\right) = \vec{F} \cdot \vec{v} \).


  • Power is the scalar dot product of the force vector and the velocity vector.


Why other options are incorrect:

Force dot displacement is Work. Work and time are scalars, and their division (not dot product) gives Power.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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