Phinally Phriday!

And, phinally, the sun has peeked out. I will take this as a good omen...

Today was kinematics for B, C and F Blocks, which nicely capped off our stepwise investigation of the descriptors of motion (displacement, velocity, acceleration). Kinematics asks and answers questions about an object's motion, but what it does not address is the cause of the motion or the factors promoting a change in the motion. That's dynamics, and we'll catch that very soon. The homework problems are designed to give you practice in working with these formulas and, I strongly urge folk to really give them a try before looking up answers. Write down all your information and identify which variable each piece represents. Choose a formula to start working with that uses that information, or could be used to get you another piece of information with what you already have provided. Plug your variables into the formula and be very mindful of signs. Evaluate your answer logically and with common sense - does it seem right or not... Create a good problem-solving strategy now, because we are going to be doing this until June...

E Block discussed their Ball Toss lab and evaluated their results in light of our previous work on kinematics. The tossed ball is an example of an object in free-fall (if we assume friction is negligible, which our results said wasn't a bad assumption) and that was the topic of today's lecture. Free-fall motion is motion where the only force acting on the object is gravity. Anything tossed into the air or dropped from a height, without any additional propulsion supplied, is a candidate for free-fall. We spent time explaining the patterns of motion associated with free fall (lose velocity as rises, gains velocity as falls) in terms of our knowledge of the interplay between acceleration and velocity and added a few items to our mental tool box (acceleration due to gravity is constant and at the top of a rise and object's velocity is 0 m/s) to help set up and solve problems. On Monday, you will do an activity to demonstrate free-fall motion and establish experimentally a value for acceleration due to gravity.

Have a great weekend!