Question

Forces
(1) Kim takes a bathroom scale into an elevator for a physics experiment. She notices the scale reads 680 N when the elevator is at rest on the 10th floor of the building. The scale reading changes to 800 N as the elevator moves up and then goes back down to 680 N. As the elevator approaches the 25th floor the scale reads 600 N. What is the magnitude of the acceleration of the elevator at this point?
(2) Block A, 45 N, is at rest on a table, and Block B, 25 N, is suspended as show below. What is the magnitude of the minimum force of static friction to hold both blocks at rest? This is a look-alike of the picture: http://i.stack.imgur.com/nMkXx.png
(3) Also, this is the same exact question as #2, but this time it's asking for the minimum coefficient of static friction required to keep both blocks at rest.

Thanks, I'm trying to study for the AP Physics exam :)

Answer 1

as the elevator travels up the shaft what accelerations will act in the opposite direction?