Forces, elevator, acceleration -- I have the answer, just please help explain it...

  • #1

Homework Statement


When a 45-kg person steps on a scale in an elevator, the scale reads a steady 480 N. Which of the following statements must be true? There could be more than one correct choice.
a) The elevator is accelerating upward at a constant rate
b) The elevator is moving downward at a constant rate
c) The elevator is moving upward at a constant rate
d) The elevator is accelerating downward at a constant rate
e) From the given information, we cannot tell if the elevator is moving up or down

Homework Equations


F = ma
Fg = mg

The Attempt at a Solution


From the equation, I know that the Fg is (45)(9.8) = 441.
I think the answer is a. But my textbook says that it is both A and E. Can someone help explain why? Thanks in advance :)
 

Answers and Replies

  • #2
Doc Al
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I think the answer is a. But my textbook says that it is both A and E. Can someone help explain why?
Hint: "moving up or down" refers to velocity, not acceleration. What's the difference?
 
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  • #3
oh ok gotcha thank you :)
 

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