A sphere of mass m, is held between two smooth inclined walls. For `sin37^(@)=3//5`, the normal reactions of the wall (2) is equal to

Options

A. `(16mg)/(25)`
B. `(25mg)/(39)`
C. `(39mg)/(21)`
D. none of these

Answer

D

Explanation

(d)`N_(1) sin 37^(@)=N_(2) sin 74^(@)`
`implies " " N_(1)=2N_(2) cos 37^(@)`

Now, `" " N_(1) cos 37^(@)-N_(2) cos 74^(@)=mg`
`implies 2N_(2) cos^(2)37^(@)-N_(2)(2 cos^(2) 37^(@)-1)=mg `
`implies 2N_(2)(16/25)-N_(2)((32)/(25)-1)=mg`
`implies" " N_(2)=mg`