Question

The blocks of masses `2kg, 3kg` and `5kg` are connected by light inextensible strings as shown. The system of blocks is raised vertically upwards by appling a force `F_(0)=200N`. Find the common acceleration and tensions in the strings.

Answer 1

`uarr:200-T_(1)-20=2a` (i)
`uarrT_(1)-T_(2)-30=3a` (ii)
`uarrT_(2)-50=5a` (iii)
Adding (i), (ii) and (iii), we get
`100=10arArra=10m//s^(2)`
`T_(1)=160N`
`T_(2)=100N`
Taking three blocks together as a system

`uarr:200-100=(2+3+5)a`
`a=10m//s^(2)`

`200-50-T_(2)=(2+3)a`
`150-T_(2)=5xx10rArrT_(2)=100N`

`T_(1)-80=(3+5)a`
`T_(1)-80=8xx10rArrT_(1)=160N`
Note`:` There are various ways to take blocks as a system.