A boy weighing 42 kg eats bananas whose energy is 980 calories. If this energy is used to go to height h fing the value of h.

Explanation

Energy gained by the boy in eating bananas = `980 "calorie" = 980 xx 4.2 J` .
If m is the mass of the boy, the potential energy gained by the boy in going up through a height h is mgh. In SI,
energy = potential energy
`980 xx4.2 = "mgh" , 980 xx 4.2 = 42 xx9.8 xx h`
` h= (980xx4.2)/(42xx9.8) = 10m`