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प्रश्न
A moving object of mass 30 kg has 60 J of kinetic energy. What is its speed?
संख्यात्मक
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उत्तर
K.E = `1/2` mv²
60 = `1/2` (30) (v)²
or v² = 4 m/s
or v= 2 m/s
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