11/18 physics update and homework due 12/2

Hi folks,

Today we went did another fairly complex lab where I had the students find acceleration, terminal velocity, gravitational force and friction force of a system using a ball and a ramp.  The students had to really think about all the formulas we've been using, as well as think about last week's lab.  It was quite a mind bender and they did a great job.

Homework for 12/2 is to use the Phet simulation Forces and Motion to answer the following questions.

Here's the link http://phet.colorado.edu/en/simulation/forces-and-motion

Click on the picture of the crate and drag to the right.  Notice that as you do there are two force vectors.  One is for the force the man is applying and the other is the friction force.  

1.  What happens to the friction force the second the crate begins to move?  Why?

2.  What is the minimal amount of force you need to apply to get the crate, filing cabinet, sleepy dog, refrigerator, and textbook to move?   (You may want to use the "Applied Force" slider for this.)  How does this relate to mass?

3.  If you stop applying force to any of the objects what happens on wood?  How about on ice? (Use the radio buttons in the upper right hand side to switch.)  Describe what's happening there using Newton's First Law and then by using Newton's Second Law.

4.  Click on the radio button for sum of forces.  What is that green arrow showing?

Click on the "Friction" tab at the top of the screen and do the following questions.

5.  What happens to the pushed objects as you increase and decrease the amount of friction?

6.  What happens to the Fg and the Fn if you change the gravity?

7.  What happens to the Fg and the Fn if you change the object mass?

Click on the Force Graphs tab at the top of the screen for the following questions.  Click on the acceleration and velocity buttons in the bottom right to bring up those graphs.

8.  Mess with the forces a bit and then draw all three of the graphs that was created by something you tried.  Label the graph at any location where change took place.  Notice the correlation between force, acceleration, and velocity.

9.  Turn "ice" on and draw another three labeled graphs.  

10. With "ice" and "bouncy walls" on draw another 3 labeled graphs.

11/11 physics update and homework due 11/18

Hi folks,

Today we took a look at some strategies to handle some more 2 dimensional motion problems. Also, we did a lab/practicum where we found out many different aspects of a lego catapult.

The homework for this week is to finish whatever data/calculations you weren't able to finish in class regarding the catapult lab. Here is the list of the data.

Top Horizontal Speed
Horizontal acceleration
Top Vertical Speed
Vertical Acceleration
Force
Mass
Distance
Acceleration of Throw
Time of Throw
Resultant Velocity


Also, complete the following .pdf. It will be using another one of those PHET simulations and it should be quite a bit of fun.

Recording of 11/11 Physics Class: Newton's Second Law

Way to go, ScienceJim! Your video's now on YouTube. Physics week 11: Newton's Second Law. Want to spread the word about your newest video? Share your video We've sent this email to sciencejim-6785@pages.plusgoogle.com. You can unsubscribe from notifications for finished uploads by visiting Email Preferences. ©2013 YouTube, LLC 901 Cherry Ave, San Bruno, CA 94066

11/4 Physics update and homework due 11/11

Hi folks,

Today we began our venture into Newton's Laws.  To be honest, everything we've been working with so far has led up to this.  Velocity, acceleration, vectors, linear motion has all been leading up to us gaining a strong understanding of Newton's three laws of motion.  Today we began with Newton's first law, an object in motion stays in motion and an object at rest stays at rest unless a force acts against them.  

Homework for this week is to:

Read pgs. 43-55

Review Questions pg. 56 #'s 1-10

Also, I want to get a bit deeper into these vector questions so please try to answer the following questions.  Let me know if you need some help on these.  I gave some clues in the first question.

1. a. Suppose that a boat was moving directly across a current with a velocity of 3 m/s, North and the motor boat  was moving with a velocity of 4 m/s, East. What would the resultant velocity of the motor boat be. (i.e., the  velocity relative to an observer on the shore)? 

b. If the width of the river is 10 meters wide, then how much time does it take the boat to travel shore to shore?  (For this, just forget about the current.  How long would it take the boat to get from shore to shore (go 10 meters) moving at 4m/s?)

c. What distance downstream does the boat reach the opposite shore?  (Use the time in part b for this.  How far downstream would the boat travel in that amount of time?)

2. A motor boat traveling 4 m/s, East encounters a current traveling 7.0 m/s, North.

a. What is the resultant velocity of the motor boat?

b. If the width of the river is 80 meters wide, then how much time does it take the boat to travel shore to shore?

c. What distance downstream does the boat reach the opposite shore?

3. A motor boat traveling 6 m/s, East encounters a current traveling 3.8 m/s, South.

a. What is the resultant velocity of the motor boat?

b. If the width of the river is 120 meters wide, then how much time does it take the boat to travel shore to  shore?

c. What distance downstream does the boat reach the opposite shore?

Video for 11/4 Physics Class: Newton's First Law

Way to go, ScienceJim! Your video's now on YouTube. Physics 2013 Week 10 Want to spread the word about your newest video? Share your video We've sent this email to sciencejim-6785@pages.plusgoogle.com. You can unsubscribe from notifications for finished uploads by visiting Email Preferences. ©2013 YouTube, LLC 901 Cherry Ave, San Bruno, CA 94066