First Scribe Post! (Class - Thursday, February 11, 2010)

Hi Classmates :)

Today, we continued our studies on Relative Velocity. In a nutshell... we discussed how frame of reference is a key thing to remember when it comes to relative velocity - all motion is relative to an observer. For example, a person walking forward at 2 m/s on a ship would appear to be walking faster to an observer on shore because the velocity of the ship would be added to the person's ground velocity. So if the ship was moving at 10 m/s, the person's velocity relative to the observer on shore would be 2 m/s + 10 m/s = 12 m/s.
So, when solving problems that involve relative velocity, the vectors of the velocities are added.

With that in mind, we also went over yesterday's homework questions from the two sheets, one entitled
4. Study Guide (on relative velocities):

The answers are as follows:
21. A
22. C
23. D
24. A, B, C, and D
25. B
26. D

and Physics 40S Relative Motion:

Case One: a) 135 km/h [E]

Case Two: a) 250 km/h [W], b) 250 km/h [E]

Case Three: a) 10 km/h [W], b) -10 km/h or 10 km/h [E], c) 70 km/h [W]

That wrapped up our one-dimensional relative motion for the lot as we moved on to two-dimensional relative motion with the worksheet... Grade 12 Physics: Relative Velocities Questions. We completed this in class, Ms. K having given us the answers, PLUS she posted them on our blog for us (check previous post). Yay thanks Ms. K. The worksheet had some 1D relative motion questions as well, but the more challenging ones (to me, lol) were the 2D relative motion questions. Since the answers and solutions have been posted, check them out for reference as you will also need to complete our two brand new worksheets (Relative Motion Problems and Relative Velocity) for homework!

So that pretty much sums up today's class.

Remember! Our test on Relative Motions has been moved from Tuesday, February 16 to Wednesday, February 17. And... finish those two homework sheets!

The scribe for next class will be Praisia.