How do I relate Food Calories to Energy ?

What is Energy? There are two fundamental components of

the physical world:◦ Matter ◦ Energy

Physics spends a lot of time dealing with energy and Chemistry with matter.

Actually the two concepts are best understood together.

Energy is the ability to do work.

Everyday meaning of work.

Scientific meaning of work.

What is Energy?

Work = Force x distance x Cos Ɵ

W = F x d x Cos Ɵwhere,

F = force in Newton’sd = distance in metersW = work, in Newton meterƟ = angle between the force and displacement vectors, in degrees

We are doing work when we exert a force on an object over a distance and the force causes the displacement of the object.

Work

What are the units of measure for Work?

Work

1 N m = 1 Joule

A Joule is an amount of energy just as a calorie is an amount of energy. The two are related using the following conversion:

1 calorie = 4.18 Joules(Remember 1Calorie = 1000 calories)

Let’s do some example calculations.

What is a Newton meter

Work Done on a BallLet’s look at the simple task of rolling a ball.