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How much work is needed to be done on a ball of mass 50g to give it a momentum of 5kgms^-1 ? |
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Answer» initial VELOCITY ( u ) = 0 m/sfinal velocity ( v ) = ?mass ( m ) = 50 g = 50 / 1000 kg = 0.05 kgMomentum ( p ) = 5 kg m/sFormula :Momentum = mass × velocityCalculate the final velocity :5 kg m/s = 0.05 kg × v= > v = 5 kg m/s / ( 0.05 kg )= > v = 100 m/sFormula :Work = change in kinetic energy = 1/2 m v² - 1/2 m u²1/2 m u² = 0 because u = 0Hence work = 1/2 m v²Find the workW = 1/2 m v²= > W = 1/2 × 0.05 × (100)²= > W = 1/2 × 0.05 × 100 × 100= > W = 1/2 × 5 × 100= > W = 5 × 50 = > W = 250 JANSWER :The work done is 250 J |
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