Question

A lamp hangs vertically from a cord in a descending elevator that decelerates at 1.4 m/s2. (a) If the tension in the cord is 91 N, what is the lamp's mass

Answer 1

Answer:8.125 kg

Step-by-step explanation:

Given

deceleration of elevator
`a=1.4\ m/s^2`

suppose T is the tension in the cord

therefore net force on lamp is

`F_(net)=T-mg`

`F_(net)=ma`

direction of a and g is in the same direction

`T-mg=m(1.4)`

`T=m(g+a)`

`m=(T)/(g+a)`

`m=(91)/(9.8+1.4)`

`m=8.125\ kg`