A rubber cord has a cross -sectional area `1 mm^(2)`and total unstretched length`10.0cm`. It is streched to `12.0 cm` and then released to project a missile of mass 5.0 g.Taking young's modulus Y for rubber as `5.0xx10^(8) N//m^(2)`.Calculate the velocity of projection .

Explanation

Tension in the cord=
`YA/L Deltal=(5xx10^(8)xx1xx10^(-6)xx2xx10^(-2))/(10xx10^(-2))=100N`
When the mass is released, elastic energy stored=
Kinetic energy of mass
`implies1/2 F Delta l=1/2 mv^(2)`
`v=sqrt((FxxDelta l)/m)=sqrt((100xx2xx10^(-2))/(5xx10^(-3)))=20ms^(-1)`