You are conducting an experiment inside an elevator that can move in a vertical shaft. A load is hung vertically from the ceiling on a string, and is stationary with respect to you. The tension in the string is measured to be 10% less than the weight of the load. No other forces are acting on the load. Which of the following statements about the elevator are correct?

Question

asapbleh · Answer

The elevator is an inertial frame of reference.
	 The elevator is not an inertial frame of reference.
	 The elevator may be at rest for the duration of the entire experiment.
	 The elevator may be moving at a constant velocity upward.
	 The elevator may be moving at a constant velocity downward.
	 The elevator must be accelerating

asapbleh · Answer

State that all apply.

badhi · Answer

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If you just hang an object on a string in an inertial frame of reference, $T_1$ will be equal to $Mg$. If its accelerating upwards, from $F=ma$, $$T_{\uparrow}-Mg=Ma\ T_{\uparrow}=M(g+a)\
T_{\uparrow}>Mg$$ If its is accelerating down, $$-T_{\downarrow}+Mg=Ma\T_{\downarrow}=M(g-a)\T_{\downarrow}<Mg$$From this we can come to following conclusions,

1. If the object is in an inertial frame of reference, The tension of the string is same as the weight of the object
2. If the object is accelerating upwards, The tension of the string is greater than the stationary tension.
3. If the object is accelerating downwards, The tension of the string less than the stationary tension.

Use above conclusions to find the answer