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Catalyst – Thursday 20 th 1.Object A is sitting 50m above the ground, Object B is sitting 5m above the ground. They are the same size, which has more potential.

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Presentation on theme: "Catalyst – Thursday 20 th 1.Object A is sitting 50m above the ground, Object B is sitting 5m above the ground. They are the same size, which has more potential."— Presentation transcript:

1 Catalyst – Thursday 20 th 1.Object A is sitting 50m above the ground, Object B is sitting 5m above the ground. They are the same size, which has more potential energy? 2.Why does a roller coaster lose some energy while running on the tracks? Where does that energy go? 3.Calculate the kinetic energy of a 7 kg truck moving 3 km/s. 4.Calculate the potential energy of a book that is sitting 10 m above the ground and has a mass of 3kg. 5.Define work in your own words. Define power in your own words. Essential Questions: How are work and energy related? How does energy affect the motion of an object?

2 Catalyst – Thursday 20 th 1.Object A is sitting 50m above the ground, Object B is sitting 5m above the ground. They are the same size, which has more potential energy? 2.Why does a roller coaster lose some energy while running on the tracks? Where does that energy go? 3.Calculate the kinetic energy of a 7 kg truck moving 3 km/s. 4.Calculate the potential energy of a book that is sitting 10 m above the ground and has a mass of 3kg. 5.Define work in your own words. Define power in your own words. Essential Questions: How are work and energy related? How does energy affect the motion of an object?

3 (7) Catalyst & Answers (5) Review Exit Ticket from Yesterday (30) Stations – 6 minutes at each station (8) Peer Grading stations (20) Quest!! (13) Start Work Notes (7) Exit Ticket

4 Review Wednesday’s Exit Ticket 1.When a rock is dropped from a height of one meter, the graviational potential energy of the rock is converted to kinetic energy. When the rock hits the floor and does not bounce, what happends to the kinetic energy of the rock? A.The energy is converted to heat and sound. B.The energy is destroyed and cannot change form. C.The enrgy is converted to chemical energy. D.The energy is reteurned to gravitational energy. 2.When one form of energy is converted into other forms of energy, what happens to the total amount of energy? A. Varies throughout the conversion. B.Increases because some energy is created. C.Remains constant throughout the conversion. D.Decreases because some energy is destroyed.

5 Catalyst – Friday 21 st 1.Name the units that is used for energy. 2.If you saw a plane flying in the sky, which type of energy is it demonstrating? Potential or Kinetic energy? 3.Define work. What do you consider to be work? 4.How is work and motion related? 5.Provide the formulas for both kinetic energy & potential energy. Essential Questions: How are work and energy related? How does energy affect the motion of an object?

6 Catalyst – Friday 21 st 1.Name the units that is used for energy. Joules 2.If you saw a plane flying in the sky, which type of energy is it demonstrating? Potential or Kinetic energy? It’s both! It’s really high in the sky but it’s also moving! 3.Define work. What do you consider to be work? The effort you put into moving something. Moving a heavy box. 4.How is work and motion related? When you want to move something you either push or pull the object so you are using energy causing you to work. 5.Provide the formulas for both kinetic energy & potential energy. Kinetic Energy: KE = ½ mv 2 ; Potential Energy: PE g = mgh Essential Questions: How are work and energy related? How does energy affect the motion of an object?

7 Agenda (7) Catalyst & Answers (8) Revisit Yesterday’s Exit Ticket questions (30) Work & Power Notes with video (20) Graded Independent Work (10) Start Simple Machines (5) Exit Ticket

8 Unit 8 - Energy Heat Temperature Thermal Energy Work Power Kinetic Energy Potential Energy

9 ET: Thursday 20 th Obj. 3.1.2 1.A construction worker hit a solid steel wall with a sledgehammer, but the wall did not move. What happened to part of the energy exerted by the worker? A. Was destroyed by the steel wall. B.Was converted into heat. C. Disappeared into the atmosphere. D.Was stopped by the hard surface.

10 ET: Thursday 20 th Obj. 3.1.2 2.An automobile engine transforms chemical energy of fuel primarily into? A. Electrical energy and light energy. B.Electrical energy and mechanical energy. C.Thermal energy and light energy. D.Thermal energy and mechanical energy.

11 Work Work is the result of a force that causes the movement of an object. WorkNot Work Why?

12 Work or Not Work? CFU #2 Work or Not Work? : If there is a force and distance involved, work has been done on the object. ___ When pushing a 1000 N car 20 meters? ___ When lifting a rock off the ground? ___ When holding a book in their hands? ___ When pushing hard against a brick wall? ___ When walking up the stairs?

13 Work Formula Work = Force (N) x distance (m) Work is energy and is measured in joules. It is how we do things. Example 1: A ball with a weight of 30N is kicked 2 meters in the air. What work has been done? W = F x D W = (30N)(2m)W = 60 Joules

14 Essential Question 1.How are work and energy related? ◦What is work? ◦How is work done? ◦What happens when you do work? ◦Where does that energy go?

15 Essential Question 1.How does energy affect the motion of an object? ◦What is motion? ◦What type of energy is motion? ◦What if you increase the Kinetic energy? What happens to the object? ◦What else increases?

16 Power Power is the rate at which you do work. Power is measured in watts.

17 Power Formula (video) Power (Watts) = work (Joules) / time (s) Example 1: An electric motor does 200 Joules of work in 12 s. Find the power. P = W/TP = 200J / 12s P = 16.7 watts

18 Our Formulas Work(J) = Force(N) x distance(m) Power(W) = Work(J) / time(s)

19 Guided Practice #1 You push a box with a force of 25N 5 meters. How much work did you do? W= Force x Distance, W= (25N)(5m) W = 125 joules of work A furniture mover lifts a box weighing 500N into the back of his truck which is 1.5 meters above the ground. How much work has been done? W = F x D, W = (500N)(1.5m) W= 750 joules of work

20 Guided Practice #2 You do 45 J of work in 3 seconds. How much power do you use? P= W/T, P = 45J / 3s P= 15 watts If 30 Joules of work has been done to move a box 10 meters, what force was applied? W= F x D => F= W/D, F = 30J / 10M F= 3N

21 Work and Power Joe pushes a box with 50 N of force across a distance of 12m. If it took him 8s to push the box, how much power did he use? What must we find first? Work! W = F x D = 600 joules Then… Power: P = W/T = 75 watts.

22 Exit Ticket - Work and Power Obj. 3.1.4 1. What determines if work has occurred or not? 2. If I use 10N of Force to push an object 3m, how much work has been done? 3. What does power measure? 4. If 200J of work is done in 6 seconds, what is the power of this machine? 5. If a 15W lightbulb is on for 30 s, how much work has been done?


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