Question
A 70kg man stands on a bathroom scale in an elevator. As the elevator starts moving, the scale reads 90kg
Is the elevator acceleration up or down, is the elevator moving up or down?
Is the elevator acceleration up or down, is the elevator moving up or down?
Answers
jai
i think you mean it's weight (units in N), because mass is constant.
anyway, since the weight increased, the elevator accelerates and moves up. :)
anyway, since the weight increased, the elevator accelerates and moves up. :)
Damon
Force up on man - weight of man = m a up
F scale - m g = m a
Fscale = 90*9.8
90*9.8 - 70*9.8 = 70 a
a = 20*9.8 /70
the acceleration is up
since we started from rest, we will be moving up but have not gained any speed yet
F scale - m g = m a
Fscale = 90*9.8
90*9.8 - 70*9.8 = 70 a
a = 20*9.8 /70
the acceleration is up
since we started from rest, we will be moving up but have not gained any speed yet