1.

A batsman deflects a ball by an angle of 45^(@) without changing its initial speed which is equal to 54 km/h. What is the impulse imparted to the ball ? (Mass of the ball is 0.15 kg.)

Answer»

Solution :LetI andjbe unitvectorin X and y directionrespectively.
`P_(1)= mv_(1)`
`p_(2) = mv_(2)`
and `theta= (45^(@))/( 2) =22.5^(@)`

HENCE `p_(1) cos theta ` and `p_(2)cos theta`are insamedirectionmagnitudebut in oppositedirectionalsohencetheycanceleachotherin x-direction
compomentin y- direction
`Delta vec(p)=p_(2)cos theta- p_(1) cos theta (- j)`
`= p costheta j +p costheta HAT(j) `
=2 ` cos theta `
Impulseofforceon ball
`2 p cos theta`
` 2xx0.15xx 15 xxsin67.5^(@)`
=`4.5xx 0.9239`
SecondMethod

`p_(2)= mv[cos 45hat(j)+ sin45hat(j))`
`=mv [cos45 +1) hat(j )= sin 45^(@) ]`
`=2.22 sqrt(1.707^(2)) + (0.707)^(2))`
`=4.2 N`


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