A) 800 N
B) 1200 N
C) Zero
D) 400 N
Correct Answer: B
Solution :
Key Idea: When lift is moving upwards, it weighs more than actual weight of man by a factor of ma. Mass of man M = 80 kg Acceleration of lift, \[a=5\,\,m/{{s}^{2}}\] When lift is moving upwards, the reading of weighing scale will be equal to R. The equation of motion gives R - Mg = Ma or R = Mg + Ma = M (g + a) \[\therefore \] \[R=80\,(10+5)\,=80\times 15\,=1200N\]You need to login to perform this action.
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