Download Chapter 5

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Thermal conduction wikipedia, lookup

Solar air conditioning wikipedia, lookup

Transcript
Chapter 5
Energy
Energy and Work
•
•
•
•
Energy – the ability to cause change.
Kinetic energy – energy in the form of motion.
Potential energy – stored energy.
Work – the transfer of energy through motion.
– Work = Force x Distance
– W = FD
– Units = Joules (Newtons x meters)
Conservation of Energy
• Mechanical energy – the total amount of
kinetic and potential energy in a system.
• Law of conservation of energy – states that
energy can change form but it cannot be
created or destroyed under ordinary
conditions.
Human Energy
• Calorie – a unit used by nutritionists to
measure how much energy we get from
specific foods.
– 1 calorie ( = 1 kilocalorie) – 4180 Joules.
– Each gram of fat supplies 9 calories of energy.
Temperature and Heat
• Temperature – a measure of the average kinetic
energy of the particles in a sample of matter.
• Thermal energy – is the total energy of the
particles in a material.
• Heat – the thermal (or internal) energy that flows
from something with a higher temperature to
something with a lower temperature. (i.e. heat is
energy transferred between objects at different
temperatures.
Thermal Pollution
• Thermal pollution – when waste heat
significantly changes the temperature of the
environment.
Measuring Thermal Energy
• Specific heat – amount of energy it takes to raise
the temperature of 1kg of a substance by 1o C.
• Thermal Energy Equation
–
–
–
–
–
Q = mc∆T
Q is change in thermal energy
m is mass
c is specific heat
∆ is the final temp. – the initial temp.