Solving Scale in an Elevator: N-W=ma?

[nrc_8706]

you are standing on a scale in an elevator. the scale reads 176lb when the elevator is at rest. the elevator begins to accelerate upward at 12ft/s^2. what is the reading of the scale?


i converted 176lb to 80kg. i know the sum of all forces equals mass*acceleration

but i don't know what to do next? is it N-W=ma?

 

[Doc Al]

is it N-W=ma?

Yes, it's just Newton's 2nd law.

Also: No need to change units. What's the acceleration due to gravity in the given units of ft/s^2?

 

[nrc_8706]

?

u said don't change the units but if the equation is N=ma+W what is m? do you divide 176lb by 9.8?

 

[Doc Al]

What is g in units of ft/s^2 ? (Look it up if you don't know.)