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F=ma question

  • Thread starter allora_97
  • Start date
  • #1
13
0

Homework Statement


A person weighing 0.6 kN rides in an elevator
that has a downward acceleration of 3 m/s2.
The acceleration of gravity is 9.8 m/s2 .
What is the magnitude of the force of the
elevator floor on the person?
Answer in units of kN.


Homework Equations


F = ma


The Attempt at a Solution


Is the downward acceleration of the elevator and gravity in the same direction, so should the acceleration in the formula equal the sum of the acceleration of the elevator and gravity.
Or are they in opposite directions?
 

Answers and Replies

  • #2
ideasrule
Homework Helper
2,266
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What do you think? Do you feel lighter on an elevator accelerating downwards, or heavier?
 
  • #3
13
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lighter, so would is acceleration due to gravity upwards?
 
  • #4
ideasrule
Homework Helper
2,266
0
Acceleration due to gravity is downwards because gravity doesn't change; it depends only on the Earth. However, the effect of the elevator's acceleration counteracts the effect of gravity.
 
  • #5
13
0
thanks
 

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