3/25Physics update and homework due 4/1

Hi folks,

Today we took some time to do a lab based on the material we have been covering lately.  In the lab, we measured the gravitational potential energy of a falling object and we compared that to the work done by that object on another object to find the energy efficiency of the system.   This encouraged some careful data collection as well as allowing us to put some of our new formulas to use.

Two assignments for homework next week.

1.  Please answer the questions on the Energy Efficiency Lab Question and Answers .pdf.  

2.  Please do the enclosed Energy Problem Set with Answers .pdf

3/18 Physics Recording - Potential Energy and Kinetic Energy

https://youtu.be/dOnX2A7DpYU

3/18 Physics Update and homework due 3/25

Hi folks,

This week we explored the ideas of potential energy and kinetic energy.  We also took a good look at the concept of gravitational potential energy.

For homework this week:

Read pages 111 - 117 in the text book.

Do questions 6 - 20 on pages 119 and 120.

Do Plug and Chug 1- 10 on page 120.

I've included answers below.

3/11 Physics Recording - Levers

https://youtu.be/Q3gWtVd5vjk

3/11 Physics Class update and homework due 3/18

Hi folks,

Today we continued to explore the relationship between force, distance and work as we took a look at the lever.  We discussed the three classes of lever and then did a lab where we could clearly see the effect of the placement of the fulcrum on the effectiveness of the lever.

For homework this week please do the following questions.  I've included your data sets so you can see your numbers.

1. What happened to the effort force as the fulcrum got closer to the load? 

2. What happened to the effort force as the fulcrum got farther from the load? 

3. What happened to the load force as the fulcrum got closer to the load? 

4. How about when the fulcrum got farther from the load? 

5. If you wanted to lift an object that you couldn't lift by yourself, where would you put the fulcrum? Close to, or far from the load? 

6. What relationship does distance have to force in regards to the lever?

7.  Make a graph with "Distance from the Load" on the x axis (the horizontal one) and "Effort Force" on the y axis (the vertical one).  Please use graph paper for this.

8.  We've stated again and again that simple machines do not change how much energy must be used to do a job.  So, what happened in this lab where we can clearly see that work in usually is not equaling work out?  Are we breaking the law of conservation of energy?  Nope, that cannot be broken so what is going on?  Something is not being measured/taking into consideration in this lab.  What is it?  

EXTRA CREDIT OPPORTUNITY!!  Once you answer #7 and know what is not being measured, can you figure out a way to calculate, using numbers you've already measured, what is missing?

ALSO, we haven't done much work with conversion in class and it's a good idea to be familiar with it.  Remember that energy can change forms and science has a variety of different units for energy depending on which form it is in.  This worksheet is a way to spend some time getting to know the different forms of energy and how they relate to one another.

I've included the answers for you so you know if you are on the right track.

ANOTHER EXTRA CREDIT OPPORTUNITY!!!  Eat a meal, then figure out how many calories you just ate by using one of many different websites or apps. (Something to keep in mind here, food calories are really KCals so be sure to use the right conversion factor. If a burger is 800 calories that's really .8 kcals)  Now convert that to Joules.  Now convert that to how much gasoline that would be.  Last but not least, if the energy in your meal could be converted in order to move a car, how far would the car go?  (Feel free to use the internet to find the miles per gallon of any automobile you wish.  I'd recommend a fuel efficient car if you want to go anywhere.  :)   )

Recording for 2/25 Physics class - Simple Machines

Hi folks,

I didn't have my camera with me today so I went back in time and pulled out a lecture from a year ago on the same material. Enjoy!


https://youtu.be/ATf3s7k0kog?t=952

2/25 Physics update and homework due 3/11

Hi folks,

First off NO CLASS NEXT WEEK!!  It's our spring break.  Enjoy the time off everyone!

This week we dove a bit deeper into the concept of energy and work by taking a look at simple machines.  We did a lab were we observed the relationship between force, distance and work as it applies to pulleys.  

For homework this week,

Read this website, starting on the introduction page and finishing on the terminology page (just keep clicking through).

Answer the following questions regarding the lab we did this week in class.

1.  With the pulleys, how did work out relate to work in?

2. What relationship did force have in regards to distance as you worked with the pulleys?

3. As you increased the number of pulleys, what effect did that have on the effort force? What effect did it have on the effort distance?

4. a. If you were lifting a load that required a force of 10N with one pulley, what effort force would be required?

b. Same question, but now you're using 2 pulleys?

c. How about 10 pulleys?

5. a. If you were lifting that load 1 meter, what would the work in distance be for one pulley?

b. 2 pulleys?

c. 10 pulleys?

These question refer to the reading or the lecture.

6. What is the definition of a simple machine?

7. What are 4 things simple machines do?  (Looking for the list on the second page of the website.)

8. What are 5 features of a simple machine?

9.  Name 6 simple machines.  Give me an example of each one.

10.  What is meant by the term "mechanical advantage"?

11.  When is the mechanical advantage of a slope greater?

12.  When is the mechanical advantage of a wedge greater?

13. When is the mechanical advantage of a screw greater?

14.  When is the mechanical advantage greatest for each of the 3 classes of levers?

15.  I've seen the "wheel and axel" characterized as a kind of a lever.  Can you see why this is true?

16.  How would you describe the pulley set ups you used in the lab using the definitions from this website?

17.  What is meant by input force?

18.  What is meant by output force?

19.  What is meant by "work in"?

20.  What is meant by "work out"?

21.  What meant by "load" when it comes to simple machines?

22.  What is meant by my statement "simple machines do a flippy floppy when it comes to force and distance?

23.  Do simple machines change the amount of work it takes to do a job?   (Feel free to use capital letters and exclamation points here.)