Work, Energy and Power

Question 1

What is Work?

Answer 1

The product of force and the amount of displacement along the line of action of that force.

Question 2

What do we need to calculate Work?

Answer 2

A. The Force (average magnitude and direction)

B. Displacement (magnitude and direction)

Question 3

When is Work Positive?

Answer 3

The direction of the force and direction of motion are the same.
Eg. The ascent phase of the bench press.
Throwing a ball
Pushing off (upward phase of a jump)

Question 4

When is Work Negative?

Answer 4

When the direction of the force and the direction of motion are the opposite.

Eg. Descent phase of the bench press
Catching a ball
Landing (downward phase of a jump)

Question 5

What is Power?

Answer 5

The rate at which work is done.

Question 6

What is Energy?

Answer 6

The capacity to do Work. (Scalar quantity)

Forms:

a) Potential (gravitational or elastic)
b) Kinetic
c) Electromagnetic
d) Chemical
e) Sound
f) Thermal
g) Heat
h) Electrical
i) Nuclear potential energy

Question 7

What is the Principle of Conservation of Energy

Answer 7

Energy cannot be created nor destroyed but can be transformed from one type to another.