Which principle explains the working of hydraulic brakes? MCQ with Answer and Explanation
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Question #1
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The kinetic energy of a body becomes four times its initial value. The new momentum will be:
Correct Answer: Option A
Explanation:
Kinetic energy KE = p²/(2m), where p is momentum. Thus p = √(2m·KE). If KE becomes 4 times, p_new = √(2m·4KE) = 2√(2m·KE) = 2p_initial. Hence momentum doubles. This relationship shows momentum scales with square root of kinetic energy for constant mass. Memory tip: p ∝ √KE when mass constant. This conceptual link between momentum and kinetic energy is frequently tested in competitive exams to assess depth of understanding beyond rote formula memorization. Always derive relationships when direct formulas aren't recalled.
Kinetic energy KE = p²/(2m), where p is momentum. Thus p = √(2m·KE). If KE becomes 4 times, p_new = √(2m·4KE) = 2√(2m·KE) = 2p_initial. Hence momentum doubles. This relationship shows momentum scales with square root of kinetic energy for constant mass. Memory tip: p ∝ √KE when mass constant. This conceptual link between momentum and kinetic energy is frequently tested in competitive exams to assess depth of understanding beyond rote formula memorization. Always derive relationships when direct formulas aren't recalled.
Question #2
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According to Newton's Law of Cooling, the rate of loss of heat from a body is strictly proportional to:
Correct Answer: Option D
Explanation:
Newton's Law of Cooling is a practical approximation stating that the rate of heat loss of a body is directly proportional to the difference in temperatures between the body and its immediate environment, provided this temperature difference is relatively small. The equation is dQ/dt = -k(T_body - T_surroundings).
Newton's Law of Cooling is a practical approximation stating that the rate of heat loss of a body is directly proportional to the difference in temperatures between the body and its immediate environment, provided this temperature difference is relatively small. The equation is dQ/dt = -k(T_body - T_surroundings).
Question #3
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The device that converts AC to DC is
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