In the below figure, what constant force 'P' is requried to bring the `50 kg` body, which starts from rest to a velocity of `10 m//s` in moving `7 m` along the plane ? (Neglect friction).
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Explanation

Work done by force `P` in displacing the
block by `7 m, W_(1) = (F cos theta) (S)`
`W_(1) = (P cos 30^@) 7 = (7 sqrt(3))/(2) P J`
`W_(2) = - mgh = - 50 xx 9.8 xx 7 sin 30^@ = - 1715 J`
According to work energy theorem
`W_(1) + W_(2) = (1)/(2) m(v_(2)^(2) - v_(1)^(2))`
`(7 sqrt(3))/(2) P-1715 = (1)/(2) xx 50 xx (10^(2) -0^(2)) rArr P = 607 N`.