A weight is hung by a cord from the ceiling of an elevator. From the following conditions, choose the one in which the tension of the cord would be the greatest...least?(draw force diagrams)

a) elevator descending at a decreasing spped
b)elevator at rest
c)elevator rising at constant speed
d)elevator descending at increasing speed.

can anyone please explain how to draw these... thanks for your time

3 answers

you have mg downward, and a force at the ceiling pulling upward.
Now, when going upward, there is a force = ma that accelerates the mass upward (if it is accelerating).
Total tension = ma + mg if falling (accelerating downward, a is negative.
If it is at constant speed, then a=0

what does mg stand for?

thanks for your timee