- #1

member 392791

## Main Question or Discussion Point

I don't understand conceptually how something accelerating down weighs less. For example, the elevator example of course if you have something with a string and a weight and the acceleration of the elevator increases upward as positive, you get

T - mg - ma = 0

and for acceleration down, you get

T - mg + ma = 0

This to me doesnt make sense, because shouldnt the equations be switched around because ma is + going up and - going down??

T - mg - ma = 0

and for acceleration down, you get

T - mg + ma = 0

This to me doesnt make sense, because shouldnt the equations be switched around because ma is + going up and - going down??

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