Find the direction of acceleration

In summary, the problem involves a person standing on a bathroom scale in a motionless elevator, which then starts to move causing the scale to briefly read only 0.66 of the person's regular weight. Using the equation sumF = MA, a freebody diagram is drawn and the formula N - 0.66mg = 0.66ma is obtained. The acceleration of the elevator is then calculated to be -0.66m/s^2, with a downward direction due to the decrease in mass. The mistake of -0.34mg is corrected and the final equation is -0.66 = ma. The mass is still considered to be m on the right side of the equation.
  • #1
Mustachio
9
0

Homework Statement



A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.66 of the person's regular weight. Calculate the acceleration of the elevator, and find the direction of acceleration.

Homework Equations



So I know you have to use sumF = MA to solve this problem.

The Attempt at a Solution



I drew a freebody diagram.
^
|
| Fn
.
|
| .66mg
V

And I got the formula N - .66mg = .66ma. This where I get stuck. I don't know what to do next.

As for the second part of the question, I know that the elevator is moving downward because of the decrease in mass.
 
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  • #2


The normal force is 0.66mg and the person's weight is mg.
 
  • #3


So I took that into account and got

.66mg - mg = .66ma
-.44 = .66ma
-.66 = ma.

Now I don't know what to do with the m. :\
 
  • #4


The mass is considered to still be m on the right side of the equation. Also, 0.66mg - mg = -0.34mg.
 
  • #5


Thank you. I feel very stupid right now for not noticing that arithmetical mistake.
 

FAQ: Find the direction of acceleration

What is acceleration?

Acceleration is the rate of change of an object's velocity over time. It is a vector quantity, meaning it has both magnitude and direction.

How is acceleration calculated?

Acceleration can be calculated by dividing the change in velocity by the change in time. This can also be represented as the slope of a velocity-time graph.

What is the difference between acceleration and velocity?

Velocity is the rate of change of an object's position over time, while acceleration is the rate of change of an object's velocity over time. Velocity is a vector quantity, while acceleration is a vector quantity.

How do you find the direction of acceleration?

The direction of acceleration can be found by looking at the direction of the change in velocity. If the velocity is increasing, the acceleration is in the same direction. If the velocity is decreasing, the acceleration is in the opposite direction.

Does acceleration always result in motion?

No, acceleration does not always result in motion. It can also result in a change in direction or a change in speed. For example, an object can accelerate towards a center point without actually moving.

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