Chapter 6, Problem 6.77P

(a)

Interpretation Introduction

Interpretation: The energy in a typical candy bar needs to be determined.

Concept Introduction: Sugar and carbohydrates are energy rich molecules. Sugars contains

glucose which is very important for the body. Our brain requires about 130gms of glucose per day. Fruits, vegetables etc contains glucose. Glucose is stored as glycogen in our body.

(b)

Interpretation Introduction

Interpretation: The height up to which one needs to climb to release the energy obtained from a candy bar needs to be determined.

Concept Introduction : Potential energy is given as:

  $\text{Potential}\text{energy}=mgh$

Here, m is mass, h is height and g is acceleration due to gravity.

(c)

Interpretation Introduction

Interpretation: The reason for the conversion of potential energy to work less than 100 % efficient needs to be explained.

Concept Introduction : According to second law of thermodynamics it can be stated that the total energy cannot be converted into work. Some energy is lost in converting it into work.