Energy, Work, Power

Question 1

Know how to define and apply the general concept of energy.

Answer 1

Defined as:
- The capacity to do work
- Cannot be created nor destroyed, merely transferred.
- Is conserved in the universe
- One of the best theoretical and experimentally supported facts in all of science.
- Anytime a force acts on an object it’s transferring & transforming energy
- SI Units = N*m = Joule (J)

Question 2

Know how to define, calculate, and conceptually apply work.

Answer 2

Work W:
- Is directly proportional to the
force (F) and displacement (d) relative to the angle (𝝷) of the force vector in one direction
- If more than one axis, break into component axises
- When work is done, energy is transferred.
- SI Units = N*m = Joule (J)
- 1J would lift a small 100g
apple 1 m.

W= Fdcos-
W= mg

Question 3

Know how to define, calculate, and conceptually apply the concept of conservation of energy (including kinetic and potential energy, and work)

Answer 3

Kinetic Energy (Joules = J)
- Exponentially related to the
velocity of half the mass.

Potential Energy (Joules = J)
- Is proportionate to the
product of the weight of the object and the height to which the object is at.

mechanical energy: ME = KE + PE (+ WNC)

Energy is the capacity to do work.
- The amount of work put into an object, adds to its energy.
- The change in kinetic or potential energy is the work added or lost.
- Example:
Cyclist does work, or puts energy “in” their system to climb a hill. That work can be calculated by determining the change in potential energy (mgh), change in loss of kinetic energy (.5mv2), or by calculating the work (Fdcos𝚹).

Question 4

Know how to define, calculate, and conceptually apply power.

Answer 4

Power:
- The rate work is performed
over a given time.
- Is inversely proportional to
the time (t) it takes to perform work (W) on an object.
- SI Units = 1 J/s = Watts (w)

P=W/t

Question 5

Be able to apply the concepts of work, energy, and non-conservative energy to human physiology.

Answer 5

• Our bodies use energy.
• The form of energy used
  when referring to our bodies is calories
• A calorie (c) is the amount of heat energy it takes to raise the temperature of 1g of water by 1oC = 4.184J
• 1 kcal = 4184 J