Question

A 60 kg woman stands on a scale in an elevator. What will the reading on the scale be ise elevator is accelerating downwards at 2.5 m/s^2??

Answer 1

Because the elevator is going downwards we will use the next formula

`W-T=ma`

Where W is the weight, T is the tension, m is the mass and a the acceleration.

We can calculate the weight using the next formula

`W=mg`

where g is the gravity.

We substitute the formula on the first formula and we get

`mg-T=ma`

We isolate T

`T=mg-ma=m(g-a)`

We have the next data

m=60 kg

g=9.8 m/s^2

a=2.5m/s^2

We substitute

`T=60(9.8-5)=288N`

Then we divide between the gravity

`(288)/(9.8)=29.4kg`