Download presentation
Presentation is loading. Please wait.
Published byLillian Stanley Modified over 9 years ago
1
Physics Review Day 2
2
Energy Energy is conserved in a system, it can not be created or destroyed Energy is simply defined as Work There are two types: –Potential energy –Kinetic Energy Units: Joules, J
3
Kinetic Energy Energy in motion A increase in velocity causes a great proportional increase in kinetic energy Kinetic Energy = ½(mass x velocity 2 ) KE = ½ mv 2 Units: Joules, J
4
Potential Energy Energy Stored by an object Most important type is Gravitational Potential Energy GPE = mass x acceleration of gravity x height GPE = mgh Units: Joules, J
5
Work and Power
6
Work Work is the force applied to something over a distance Work = Force x Distance W = F x d Units: Joule, J
7
Power Power is work done over time Power = Work/ time P= W/t Units: Watts, W
8
Machines A device that makes work easier
9
Simple Machines Work is done with only one movement 6 basic machines –Lever –Inclined plane –Wedge –Screw –Pulley –Wheel
10
Compound Machines Two or more simple machines are used together
11
Measuring a Machine’s Efficiency For real machines, some of the energy put in is always lost as heat produced by friction; therefore, work output is less then work input Efficiency = (Work output / work input) x 100
12
Heat Transfer Conduction, Convection, and Radiation
13
Conduction Transfer of thermal energy due to direct contact with a solid
14
Convection Transfer of thermal energy through liquids and gases
15
Radiation Transfer of thermal energy through electromagnetic waves
16
Electric Circuits Closed, conducting path that electric charges follow
17
Circuit Units Voltage –The “push” that causes the charge to move –Measured in volts, V Current –Flow of the charge –Measured in amperes, A Resistance –A material’s tendency to oppose an electric flow –Measured in Ohms, Ω
18
Ohm’s Law Relates electric current, voltage difference, and resistance Current = Voltage/ Resistance Voltage = Current x Resistance I = V/R or V = IR
19
Series Circuit Provides only one path for the current to follow (contains only one loop) To solve for resistance: –R total = R 1 + R 2 + R 3 …
20
Parallel Circuits Current follows more than one path (contains more than 1 loop) This is used in houses R total = 1/R 1 + 1/R 2 …
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.