A typical candy bar weighs about 2.00 oz (1.00 oz = 28.4 g). (a) Assuming that a

Question

A typical candy bar weighs about 2.00 oz (1.00 oz = 28.4 g).

(a) Assuming that a candy bar is 100% sugar and that 1.00 g of sugar is equivalent to about 4.00 Calories of energy, calculate the energy (in kJ) contained in a typical candy bar in scientific notation.

(b) Assuming that your mass is 67.7 kg and you convert chemical potential energy to work with 100% efficiency, how high would you have to climb to work off the energy in a candy bar in scientific notation? (Potential energy = mass × g × height, where g = 9.81 m/s2.)

Explanation / Answer

(a)

Mass of a candy bar = 2*28.4 = 56.8 g

So,

Energy in a single candy bar = 56.8*4 = 227.2 cal = 227.2*4.184 = 950.6 J = 0.9506 kJ

(b)

Putting values in the relation:

Potential energy = m*g*h

950.6 = 67.7*9.81*h

Solving we get:

h = 1.43 m

Hope this helps !

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