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Laws of Motion — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsLaws of Motion3 Marks
Question
A man of mass $70kg$ stands on a weighing scale in a lift which is moving. Upwards with a uniform acceleration of $5ms^{-2}$. What would be the readings on the scale in each case?
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Answer

Mass of the man, m = 70kg Acceleration, $a = 5m/s^2$ upward Using Newton’s second law of motion, we can write the equation of motion as: R - mg = ma R = m(g + a) = 7(10 + 5) = 70 × 15 = 1050N
$\therefore$ Reading on the weighing scale $=\frac{1050}{\text{g}}=\frac{1050}{10}=105\text{kg}$

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