An elevator and its load weigh a total of `800kg` Find the tension `T` in the supporting cable when the elevator originally moving downwards at `20m//s` is brought to rest with constant retardation in a distnce of `50m`.

Answer

`1.104 xx10^(4)N` .

Explanation

Here, `m = 800 kg, T =` ?
`u =20 m//s, upsilon = 0, s =50 m`
From `upsilon^(2) - u^(2) = 2 a s`
`a = (upsilon^(2) - u^(2))/(2 s) =(0-400)/(2 xx50) = - 4m//s^(2)`
As elevator is moving downwards
`:. T = m (g -a) = 800 (9.8 + 4) N`
`= 1.104 xx 10^(4) N` .