A mass of `2.9 kg` is suspended from a string of length `50 cm` and is at rest . Another body of mass `100 gm` which is moving horizontal with a velocity of `150 m//s` strikes it . After striking the two bodies combine together . Tension in the string , when it is at an angle of `60^(@)` with the velocity is : `g = 10 m//s^(2)`

Options

A. `135.3 N`
B. `165.5 N`
C. `142.4 N`
D. `90 N`

Answer

`(1)`

Explanation

Common velocity, `v = (m_(1)u_(1) + m_(2)u_(2))/(m_(1) + m_(2))`
`1/2(m_(1) + m_(2))v^(2) = 1/2(m_(1) + m_(2))v_(1)^(2) + (m_(1) + m_(2)) gl(1 - cos 60^(@))`
`v_(1) = sqrt((v^(2) - gl)) = sqrt(20.1)`
`T = (m_(1) + m_(2)) g cos 60^(@) + (m_(1) + m_(2))v_(1)^(2)/l`
` = 135.3 N`.