Question

One ounce of a well-known breakfast cereal contains 104 Calories (1 food Calorie = 4186 J). If 2.5% of this energy could be converted by a weight lifter's body into work done in lifting a barbell, what is the heaviest barbell that could be lifted a distance of 2.3 m??

Answer 1

482.4 kg

Step-by-step explanation:

104 calorie = 435344 J

The 2.5% of this energy equals to

435344 * 0.0025 = 10883.6 J

If this energy is converted to work done on lifting a barbell by a distance of 2.3. By the formula of Work W = force * distance then the force he exerts on the barbell is

`F = (W)/(D) = (10883.6 )/(2.3) = 4732  N`

Assuming gravitational constant g = 9.81 m/s2 then the mass of the barbell is

m = 4732 / 9.81 = 482.4 kg