Physics Work & Energy NUMS 2023
PMDC Verified Question 38 of 108
A body of mass 'm' is moving with velocity 'v'. after a short interval of time its velocity becomes double. How many time its K.E will increase of decrease?
A
2 time increased
B
2 time decreased
C
4 time increased
D
4 time decreased
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: 4 time increased
Concept:

Kinetic energy has a quadratic relationship with velocity.

Formula:

$$ K.E = \frac{1}{2}mv^2 $$

Solution:

  • Initial K.E \( = \frac{1}{2}mv^2 \).


  • New velocity is \( 2v \).


  • New K.E \( = \frac{1}{2}m(2v)^2 = \frac{1}{2}m(4v^2) = 4 \times \left(\frac{1}{2}mv^2\right) \).


  • Because 4 is greater than 1, it is a 4 times increase.


Why other options are incorrect:

Option A mistakes the quadratic relationship for a linear one (momentum doubles, but K.E quadruples). Decreasing options are illogical since speed increased.

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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