JEE Mains · Physics · STD 11 - 4.1 newtons laws of motion
A person standing on a spring balance inside a stationary lift measures \(60 \,kg\). The weight of that person if the lift descends with uniform downward acceleration of \(1.8\, m / s ^{2}\) will be \(_{-} N\). \(\left[ g =10\, m / s ^{2}\right]\)
- A \(486\)
- B \(492\)
- C \(512\)
- D \(456\)
Answer & Solution
Correct Answer
(B) \(492\)
Step-by-step Solution
Detailed explanation
When lift is at rest \(N = mg\) \(\Rightarrow 60 \times 10=600 N\) When lift moves with downward acceleration. In frame of lift pseudo force will be in upward direction. \(N^{\prime}=M(g-a)\) \(\Rightarrow 60(10-1.8)\) \(N^{\prime} \Rightarrow 492 N\)
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