Forces - Elevator 2 part question

[Larrytsai]

Hi I just needed help with a question with 2 parts. I just need to know where to start and what formula is recommended for use.

For example:
Larry is standing on a scale in an elevator, the scale reads x. The elevator accelerates upwards at x m/s/s. The elevator weighs xx. How much does the scale read now?

Also same thing but acceleration is downwards.

Thanx for the help :D

 

[faoltaem]

Do you have any formulae at all?
Do you understand the concept of what is happening when the elevator is moving?

 

[Larrytsai]

the formulas that need to be used are w=mg, f=ma
and something about Sigma F

 

[Tlocc]

You need to sum your forces before and during the elevator movement. You know what weight is, mg. You know that before the movement there should only be 2 forces and they balance out. Now you need a free body diagram for the movement. You know that the elevator is moving upwards so sum your forces again and try from there.

 

[Larrytsai]

when you say sum your forces, you mean like upwards is positive and downwards is negative so it would be Fn-W right?