An elevator weighs `4000kg` When the upward tension in the supporting cable is `48000 N` what is the upward acceleration? Starting from rest, how far does it rise in `3` seconds ?

Answer

9.9

Explanation

Mass of lift, M = 4000 kg
Weight of lift, Mg = 4000 kg wt
`=4000 xx 9.8 = 39200 N`
Upward tension, T = 48000 N
Net upward force on the lift,
F. = T-Mg =`48000 - 39200 = 8800 N`
Upward acceleration, `a = F^(.)/m = 8800/4000 = 2.2 ms^(-2)`
For upward motion `u =0, a =2.2 ms^(-2), t = 3s`
`therefore s = ut +1/2at^(2) = 0 xx 3 + 1/2 xx 2.2 xx 3^(2) = 9.9 m`