A body of mass 2 kg is moving with an acceleration of 5 m/s². The rate of change of its momentum is:
A. 10 N
B. 2.5 N
C. 10 kg m/s
D. 0.4 N
Answer: Option A
Solution (By JKExamLibrary)
According to Newton's Second Law of Motion, the rate of change of momentum is directly proportional to the applied unbalanced force. Rate of change of momentum = Force = mass × acceleration. Force = 2 kg × 5 m/s² = 10 Newtons (N). Note that '10 kg m/s' is a unit of momentum, not its rate of change.
Explanation:
Apparent frequency change depends on relative velocity between source and observer with respect to medium. Both motions contribute: f' = f(v±v_o)/(v∓v_s). Memory tip: 'Approaching ⇒ higher pitch; receding ⇒ lower pitch'. Conceptual question testing Doppler effect fundamentals, frequently examined in competitive exams.
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