Quick True/False questions about acc elevator

[niravana21]

Homework Statement

The figures depict situations where a person is standing on a scale in eight identical elevators. Each person weighs 600 N when the elevators are stationary. Each elevator now moves (accelerates) according to the specified arrow that is drawn next to it. In all cases where the elevator is moving, it is moving upward.

True or False

1.The net force on the person is zero in pictures B,G, H
2.The normal force provided by the scale is greatest in pictures A and E
3.The mass of the person is different in pictures E and F
4.The weight the scales read is the same in picture A and E
5.The scales read zero weight in all pictures.

The Attempt at a Solution

1. False-because they're acclerating
2. Not sure
3.False-mass stays the same
4.Same acc but different velocities--does that affect mass?
5. False

Please someone check this for me.

Thank you

 

[dimpledur]

Since the weight of the person is constant, the only variable force would be the normal force, which alters depending on the acceleration and its direction. However, in 4) you will notice that the acceleration is the same. What does that tell you about the normal force? Note that the normal force is what provides the reading that the scale reads.

 

[niravana21]

So in 4) the normal force would be read as the same since the acc is the same correct?

But what about 2)?

 

[dimpledur]

A and E should read the same weigh on the scale.

N-W=ma
N=ma+W
Since the weight is constant, the normal force is greatest when the acceleration is greatest in the +y direction.

 

[niravana21]

thank you very much! My other reasonings seem right, right?

Also is this considered accelerating?

"a child riding a carousel around in a circle"?