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    				| 1. | A mass is suspended from a vertica spring which is executing SHM of frequency 5 Hz. The spring is unstretched at the highest point of oscillation. Maximum speed of the mass is (take, acceleration due to gravity, `g=10m//s^(2)` )A. `2pi m//s`B. `pi m//s`C. `(1)/(2pi)m//s`D. `(1)/(pi)m//s` | 
| Answer» Correct Answer - D Given, frequency of SHM (n) =5 Hz Acceleration due to gravity (g) `=10m//s^(2)` WE know that, `T=2pisqrt((m)/(k))` But frequency, `n=(1)/(T)` `or" "n=(1)/(2pi)sqrt((k)/(m))or5=(1)/(2pi)sqrt((k)/(m))` On taking square both sides, we get `25=(1)/(4pi^(2))(k)/(m)` `k=100pi^(2)m` . . . (i) But `kA=mg` `rArrA=(mg)/(k)` . . . (ii) Now, `V_(max)=omegaA` `=(2pi)/(T)xx(mg)/(k)" "` [from Eq. (ii)] `or" "v_(max)=2pinxx(mg)/(k)" "(becausen=(1)/(T))` `v_(max)=2pinxx(mg)/(100pi^(2)m)` [from Eq. (i)] `v_(max)=(nxxg)/(50pi)` `v_(max)=(5xx10)/(50pi)` `v_(max)=(1)/(pi)m//s` | |