Question

Three block of masses `m_(1) = 10kg, m_(2) =20 kg` and `m_(3) = 30kg` are on a smooth horizontal table ,connected to each other by light horizontal string. A horizontal placed force `F = 60N` is applied to `m_(3)`, towards right find
(a) tension`T_(1)` and `T_(2)` and
(b) tension`T_(2)` if all of a sudden the string between `m_(1)` and `m_(2)` snaps.

Answer 1

(a)`T_(1) = 10a,T_(2) - T_(1) = 20a, 60 - T_(2) = 30a`

`a = ("Net pulling force")/("Total mass") = (60)/(10 + 20 + 30) =1 m//s^(2)`
On solving , we get `T_(1) = 10N,T_(2) = 30N`
(b)`T_(1) = 0,T_(2) = 20a, 60 - T_(2) = 30a`
`a = ("Net pulling force")/("Total mass") = (60)/(20 + 30) = 1.2m//s^(2)`
On solving , we get `T_(2) = 24N`