newtonian physics q's

[chiddler]

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1. In accelerating elevator scenarios, (eg "what is the apparent weight" questions) I can intuit if the elevator acceleration adds or decreases the apparent weight of the object. But how can I prove this mathematically without intuition?

example. Elevator is moving up at 10 m/s^2. What is the apparent weight of a 10kg brick inside the elevator.

 

[SaintJude]

apparent weight = magnitude of the rider's normal force

 

[MedPR]

1. In accelerating elevator scenarios, (eg "what is the apparent weight" questions) I can intuit if the elevator acceleration adds or decreases the apparent weight of the object. But how can I prove this mathematically without intuition?

example. Elevator is moving up at 10 m/s^2. What is the apparent weight of a 10kg brick inside the elevator.

I still can't get this in my head, but I know you can figure out by drawing a free body diagram. Sorry I can't be of more help.

 

[chiddler]

apparent weight = magnitude of the rider's normal force

yes. so my question is how do you know if you add or subtract the added weight from elevator acceleration without intuition?

 

[cfive22]

yes. so my question is how do you know if you add or subtract the added weight from elevator acceleration without intuition?

S = W (1 + a/g)

S is apparent weight. W is weight (mg). a is the acceleration of the system. So if you're in an elevator that is going up at the speed of gravity, S = W (1 + g/g) = 2W vs if you're in an elevator that is in free-fall S = W (1 + -g/g) = 0 = weightless. This is straight from TBR. Is this what you were looking for or did I misinterpret the question?

10 kg brick in an elevator that is accelerating at the speed of gravity. S = 10 kg*10 m/s^2 (1 + g/g)

S = 100 (2) = 200 N is the apparent weight