1. We want to solve for H v : Fill in variables from data table; H v will be the unknown

2.  To calculate percent error:  Where accepted is 2.26x10 6 J/kgC

3. 1. What does the word “fluid” mean to you? 2. List 5 examples of fluids 3. What does the word “pressure” mean to you?

4. 1. What principle describes the buoyant force? 2. What is a fluid? 3. What principle describes pressure in a fluid?

5.  Please use the rest of class to work on your review packet.  Not working on your packet will result in a loss of 2 points for today!!!  If you have any questions or need any slides, please ask.

7. Fluid: materials that flow and have no definite shape of their own

8. F=force A=area Measured in Pascals (Pa)

9.  What animal do you think exerts the greatest pressure on the earth?

11.  A child weighing 364 N stands on the ground. His feet take up an area of 0.2 m 2. What pressure does he exert on the ground?

12.  A child of mass 45 kg sits on a 5 kg 3 legged stool whose legs take up an area of 20 cm 2. a.What is the pressure exerted by the child and the stool? b.If the child leans on two legs, what is the new pressure?

13. 1. Use the rest of class to work on your homework: Density and Pascal’s Principle. It is due on Monday!

14. 1. Use the rest of class to work on practice problems 1-2 on page 303 of your classroom textbook 2. If you finish, work on your lab 3. A-Course: Problems 1-5 on p. 344 of home textbook 4. B-Course: Problems 1,2,3,5 on p. 344 of home textbook – due Wed 3/16

15.  Strategies:

16.  Density: the amount of mass per unit volume  ρ=(rho) density  m=mass  V=volume

17.  The density of brass is 8.4 g/cm 3. What is the approximate volume of a 800-g brass monkey?

18. A child exerts 4000 Pa of pressure on the ground. His feet take up an area of 0.2 m 2. 1. What is his weight? 2. What is his mass?

19.  The air pressure exerted on Earth at sea level; 1 atm = 10 5 Pa or 100 kPA

20.  Any change in pressure applied at any point on a confined fluid is transmitted undiminished throughout the entire fluid  Think of squeezing toothpaste out of a tube!

21. a hydraulic apparatus used to lift or move objects using the force created when pressure is exerted on liquid in a piston

22.  Pascal’s Principle:  Force exerted by a hydraulic lift:

23.  In a machine shop, a hydraulic lift is used to raise heavy equipment for repairs. The system has a small piston with a cross sectional area of 0.01 m 2 and a large piston with cross sectional area of 0.20 m 2. How much load can be lifted by the large piston if 150 N of force is exerted into the small piston?

24.  Please use the rest of class to finish your homework.  If you finish your homework, please meet with your mousetrap car group!!  Mousetrap cars need to be built by MONDAY MARCH 19

25.  The input piston of a hydraulic lift is 0.2 m in diameter, and the output piston is 0.1 m in diameter. How much output force will an input force of 4 N produce?

26.  Absorption of heat causes an increase in length; release of heat causes a decrease

27.  L= length  ΔL=change in length  ΔT= change in temperature  α L = coefficient of linear expansion

28.  The degree of expansion divided by the change in temperature for each material

29.  A copper pipe is 100 meters long at 5 o C. The pipe is heated to 105 o C. The coefficient of linear expansion for copper is 2.0 x 10 -5 / o C. What is the change in length of the copper pipe?

30.  You have the rest of class to work on your pre-labs. They are due at the end of class!!!  Once you finish, get together with your group and work on your mousetrap car. It is due NEXT Monday, 3/19!!!

31. Accepted Linear Expansion Values of Common Materials Material a (x10 -5 °C -1 ) Glass (ordinary) 0.09 Glass (Pyrex) 0.32 Concrete 1.20 Steel 1.24 Copper 1.76 Aluminum 2.34 Lead 2.90

32. 1. What is a Bunsen burner? 2. How does it work? 3. What are some good safety guidelines to keep in mind when working with Bunsen burners?

33. The Forth railway bridge has an overall length of 2,529 m (about 1½ miles). It is made of steel (coefficient of linear expansion = 0.000012 per °C). If the greatest difference in temperature between the coldest and hottest days is 35°C what is greatest the length the bridge can change by?

34. 1. What is the pressure on the ground of a 4 kg brick whose bottom is 0.3 m long and 0.2 m wide? 2. Turn in homework and Do Now’s

35.  Should be completely DESIGNED by Monday!!! If you have already built yours, then you are ahead of the game

36.  Get together with a group of 3-4 people to design a boat based on the specifications on your paper. Your drawing should include specific designs and measurements!!! When you are finished, check in with me.

37. Take out your boat design. Discuss your reasoning with your neighbor and list two reasons for your boat’s shape.

38. 1. What is Archimedes Principle? 2. How did it relate to yesterday’s lab?

39.  How well did your boat do yesterday? What design decisions do you think caused your success or lack thereof?

40.  An object immersed in a fluid has an upward force on it equal to the weight of the fluid displaced by the object  ρ fluid =density of the fluid  V=volume of object  g=9.8

41.  A cubic decimeter (1x10 -3 m 3 ) of a granite building block is submerged in water. The density of granite is 2.7x10 3 kg/m 3. the density of water is 1000 kg/m^3 ◦ What is the buoyant force acting on the block?

42.  Less dense materials FLOAT when mixed with more dense materials  More dense materials SINK when mixed with less dense materials

43.  Density: kg/m 3  Mass: kg  Volume: m 3  If your units are not in these, you must convert!!!

44.  Use the rest of class to work on the paper Archimedes Principle. It will be due next week!!!  You will also have a test next week!!!

45. 1. Think back to our unit on energy. What type of energy do you think a mousetrap has before it is sprung? 2. What is the area of the trapezoid?

46.  The area under the curve of a Force- distance graph is the potential energy!

47.  Pass in final car designs and Boat Labs, then head over to room 127.

48. 1. What is the buoyant force exerted on a steel object with volume 2x10 -3 m 3 floating in crude oil? The density of crude oil is 900 kg/m 3 and the density of steel is 7850 kg/m 3.

49. A gold crown (density is 19,300 kg/m 3 ) weighs 40 N in air. 1. What is the volume of the crown? 2. What is the buoyant force of the crown? 3. What will it weigh when suspended in crude oil whose density is 900 kg/m 3 ?

50.  Use the rest of class to work on the paper Archimedes Principle. It is due tomorrow!!!  Mousetrap labs are due Friday!!! Come in tomorrow with any questions about the lab!!!

51. A gold crown (density is 19,300 kg/m 3 ) weighs 20 N in air. 1. What is mass of the crown? 2. What is the volume of the crown? 3. What is the buoyant force of the crown when suspended in sunflower oil whose density is 920 kg/m 3 ??

52.  Pass in homework, then leave your things and walk over QUIETLY to room 127.

53.  Apparent weight: The weight in a given frame of reference

54.  A cubic decimeter (1x10 -3 m 3 ) of a granite building block is submerged in water. The density of granite is 2.7x10 3 kg/m 3. ◦ What is the buoyant force acting on the block? (9.8N) ◦ What is the apparent weight?

55.  Clear your desks of everything except a blank sheet of paper and a writing utensil

56.  A cubic decimeter (1x10 -3 m 3 ) of a granite building block is submerged in water. The density of granite is 2.7x10 3 kg/m 3. ◦ What is the buoyant force acting on the block? ◦ What is the apparent weight?

57. 1. What is the buoyant force exerted on a steel object with volume 2x10 -3 m 3 floating in crude oil? The density of crude oil is 900 kg/m 3 and the density of steel is 7850 kg/m 3. 2. What is the apparent weight?

58.  A steel crown (density is 7850 kg/m 3 ) weighs 40 N in air. What will it weigh when suspended in sunflower oil whose density is 920 kg/m 3 ?