Physics Work & Energy ETEA 2022
PMDC Verified Question 49 of 108
When five times momentum of a body is equal to the kinetic energy of the same body then its velocity is equal to:
A
5 m/s
B
10 m/s
C
15 m/s
D
20 m/s
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 10 m/s
Concept:

Set up an algebraic equation directly from the condition given in the word problem using standard formulas for momentum and kinetic energy.

Formula:

$$ 5p = K.E $$

Solution:

  • Substitute \( p = mv \) and \( K.E = \frac{1}{2}mv^2 \).


  • \( 5(mv) = \frac{1}{2}mv^2 \)


  • Cancel mass \( m \) and one \( v \) from both sides (assuming \( v \neq 0 \)).


  • \( 5 = \frac{1}{2}v \)


  • \( v = 5 \times 2 = 10 \text{ m/s} \).


Why other options are incorrect:

If you forget the \( 1/2 \) in the K.E formula, you get \( 5mv = mv^2 \Rightarrow v = 5 \text{ m/s} \) (Option A). Options C and D result from arbitrary arithmetic.

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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