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Do Now- 5/14. List what equation you would use to calculate the answers to the following word problems . a . A car moves a 25 m/s for 8 seconds. What distance did the car move? b . You apply a force of 16 N to push a 4 gram pencil. What is the acceleration of the pencil and you push it?
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Do Now- 5/14 List what equation you would use to calculate the answers to the following word problems. a. A car moves a 25 m/s for 8 seconds. What distance did the car move? b. You apply a force of 16 N to push a 4 gram pencil. What is the acceleration of the pencil and you push it? c. It takes 40,000 J of work to move a box 50 meters. How much force does moving the box require?
agenda • Do now (2 minutes) • Foldable notes (10 minutes) • Group Practice (10 minutes) • IP (15-20 min) • Closing (5 minutes) • Progress Reports
Reminders • Grades close for interims TOMORROW- any make-up work must be in my box by 3:45 p.m. to be counted. • I will not take any work that was due before 5/4 • See me AFTER SCHOOL for questions about grades
Foldable You need two sheets of paper Algebra Overview Density Example Velocity Example F=ma Example
Algebra Overview Rearranging equations: - You can do anything to an equation as long as you do the same to each side - Anything divided by itself is 1
Density Equation D = m/v If the density of an object is 6 g/mL it’s volume is 3 mL, what is it’s mass? Solving for: m (mass) V x D = m v x V V x D = m
Velocity equation V = d/t Anobject moves for 35 seconds at a velocity of 10m/sec. Far did it move? Solving for: d (distance) tx V = d t xt tx V = d
F=ma equation F = ma A force of 600 N is needed to accelerate a wagon 2 m/s2. What is the mass of the wagon? Solving for: m (mass) a a F = ma F = m a
Velocity equation V = d/t Anobject moves for 40 meters at a velocity of 10m/sec. How long did this take? Solving for: t (time) tx V = d t xt V V t = d v tx V = d
Develop equations for the following word problems • A train traveled with a velocity of 40 m/s for 20 seconds. How far did the train travel ?
Gold has a density of 19.3 g/cm3. What is the volume of a sample of gold that has a mass of 30 g?
You do 39 J of work to lift a book a distance of 3 meters. How much force did you apply to the book?
Independent Work Complete the practice sheet of word problems on your own. Remember to: Only use the variables necessary Step 1: Determine what you are solving for. Step 2: Determine what equation you need to use. Step 3: Rearrange the equation if necessary. Step 4: Solve problem 1. Identify Variables 2. Plug numbers into Equation 3. Solve & Include Units
CLOSING Show all your work 1. Iron has a known density of 7.87 g/cm3. What would be the mass of a 1.2 cm3 piece of iron? 2. What is the velocity of a jet plane that travels 732 meters in 8.2 seconds?
Do Now State whether you think each of the following require “work” and why. a. You push a shopping cart through the grocery store. b. You try and push a box forward but it is very heavy and does not move. c. You think through a math problem.
Do Now State whether you think each of the following require “work” and why. • You lift a coffee mug to take a drink. • b. You try to push open a door but it is locked shut and doesn’t open. • c. You ride your bike up a hill in a dream.
Work Work is done only when a force cause a change in the position or the motion of an object work = force x distance or W = F x d
Work work = force x distance or W = F x d The SI unit for force is newton (N). The SI unit for distance is meter (m). The SI unit for work is joule (J). 1 J = 1N x 1m
A fork lift moves 34m carrying a 1023N box across the warehouse floor. How much work is done by the fork lift. Step 1: Identify your variables: F = 1023 NW = ? d = 34 m Step 2: Plug numbers into correct equation • W = F x d W = 1023 N x 34 m Step 3: Solve equation • W = 1023 N x 34 m W = 34,782 J
How much work is done by a person who uses a force of 27.5N to move a grocery buggy 12.3m? Step 1: Identify your variables: F = 27.5 NW = ? d = 12.3 m Step 2: Plug numbers into correct equation • W = F x d W = 27.5 N x 12.3 m Step 3: Solve equation • W = 27.5 N x 12.3 m W = 338.25 J
Practice Problems You use 4 N of Force to lift a coffee mug .25 meters. How much work have you done? A man pushed a 5000 gram box 25 meters. This involved 150 N of force. How much work is done. A woman pushes a box with 20 N of force but cannot move it. How much work has she done?
Power The rate at which work is done (how much work is done in a given amount of time) Example: What is more tiring? Walking up a flight of stairs or Running up a flight of stairs? Both require the same amount of Work but one you do faster (faster = more power)
Power Power = Work or P = W time t Power is measured in Watts: W = 1Joule/1 second
It takes 100,000 J of work to lift an elevator 18 m. If this is done in 20 s, what is the average power of the elevator during the process? Step 1: Identify your variables: W = 100,000 J P = ? t = 20s Step 2: Plug numbers into correct equation • P = W/t P =100,000J/20s Step 3: Solve equation • P= 5000 W (or 5 kW)
While rowing across the lake during a race, John does 3960 J of work on the oars in 60 seconds. What is the power in Watts? Step 1: Identify your variables: W = 3960 J P = ? t = 60s Step 2: Plug numbers into correct equation • P = W/t P =3960J/60s Step 3: Solve equation • P= 66 W
Exit Ticket • You apply 20 N of force to lift a book a distance of 3 meters. How much work did you apply to the book. 2. If you did 48 J of work to lift a box in 4 seconds how much power did you have?
Exit Ticket • A force of 825 N is needed to push a car across a lot. Two student push the car 35 m . How much work is done? • A power mower does 450,000 J of work in 1800 seconds. What power does it develop?
Do Now Review problem. Rearrange equations to solve for the following: • Mass (F=ma) b. distance (W=Fd) c. Work (P=W/t) d. time (P=W/t)
TYPES OF ENERGY Mechanical, Electromagnetic, Electrical, Chemical, Sound and Thermal
Energy due to a object’s motion (kinetic) or position (potential). The bowling ball has mechanical energy. When the ball strikes the pins, mechanical energy is transferred to the pins! What is Mechanical Energy?
Light energy Includes energy from gamma rays, xrays, ultraviolet rays, visible light, infrared rays, microwave and radio bands What is ElectromagneticEnergy?
Energy caused by the movement of electrons Easily transported through power lines and converted into other forms of energy What is Electrical Energy?
Energy that is available for release from chemical reactions. The chemical bonds in a matchstick store energy that is transformed into thermal energy when the match is struck. What is Chemical Energy?
Sound Energy Energy transferred through a medium (ex: air, water) The changes in pressure in the air caused by sound are picked up by sensitive bones in your ears – your brain interprets these changes as sound
Heat energy The heat energy of an object determines how active its atoms are. A hot object is one whose atoms and molecules are excited and show rapid movement. A cooler object's molecules and atoms will show less movement. What is Thermal Energy?
What is Nuclear Energy? Ex: Sun, Stars, Nuclear Power Plant Energy stored in the nucleus of an atom from fission or fusion Fission – splitting an atom Fusion – fusing the nuclei of 2 atoms
QUIZ TIME! What type of energy cooks food in a microwave oven? ELECTROMAGNETIC ENERGY What type of energy is the spinning plate inside of a microwave oven? MECHANICAL ENERGY
QUIZ TIME! Electrical energy is transported to your house through power lines. When you plug an electric fan to a power outlet, electrical energy is transform into what type of energy? MECHANICAL ENERGY
QUIZ TIME! What energy transformation occurs when an electric lamp is turned on? ELECTRICAL ENERGY ELECTROMAGNETIC ENERGY
What type of Energy is shown below? NUCLEAR ENERGY
What types of energy are shown below? Mechanical and Thermal Energy (Don’t forget friction)
What type of energy is shown below? Chemical Energy
What types of energy are shown below? Electrical, Mechanical and Electromagnetic Energy
What type of energy is shown below? Sound Energy
What type of energy is shown below? Chemical Energy (yummy)
What type of energy is shown below? Thermal Energy
Rube Goldberg Machines Uses the transfer of energy to perform a very simple task in a very complex manner
Honda Cog: Rube Goldberg Machine List the following energies in your notes: • Mechanical • Electromagnetic • Electrical • Chemical • Sound • Thermal • Nuclear As you watch the video – list as many examples as you can for each (Hint: all are present except for two)