A person lifts a stone of mass 100 g from the ground to a height of 1.5 m and projects it with a speed 4 m/s . If the process takes 1.5 s then calculate power of the person .

Explanation

First we can apply work energy theorem to calculate work done by the person .
`W_("person") +W_(mg) = K_(2) - K_(1)`
` rArr W_("person") + (-0.1 xx 9.8 xx1.5) =1/2 (0.1)(4)^(2) - 0 `
`rArr " " W_("person") = 1.47 = 0.8 `
` rArr " " W_("person") = 2.27 J `
Power = `W/t = (2.27)/(1.5) = 1.51 ` watt .