Motion and Acceleration

Physics A and B reviewed their work on free-fall before moving on to a review for tomorrow's exam. I'll try and get a review video posted later this afternoon to help folks who were absent for today's review. On Thursday, we move from 1-dimensional motion to 2-dimensional motion and start off that work with a study of vectors.

Introductory Physics added acceleration to their pot of descriptors of motion. With acceleration, velocity, time and displacement, you can do a very good job describing and predicting the motion of any object (as long as we factor out friction and air resistance). We covered the definition and basic formula for acceleration and looked at how accelerated motion is presented graphically when plotting position vs. time and velocity vs. time. We also took the opportunity to bring up the special case of circular motion, which is characterized by constant, continuous acceleration. That acceleration, centripetal acceleration (caused by centripetal force) indicates the rate of change of velocity, but concentrates on the direction portion of the velocity measurements. Tomorrow, you'll get a lot more practice working with motion graphs and Thursday will bring us into working with more of the math involved with motion.

Honors Physics conducted their Projectile Motion lab today. Projectiles are objects launched into the air and acted upon only by gravity. They can be horizontally-launched, like the ball rolling off the table in today's investigation, or launched at an angle, like a kicked soccer ball. When working with 2-dimensional motion, we can look at the x-motion and the y-motion separately and make good predictions about features of the object's trajectory. Today, folks had to gather information and predict where a horizontally-launched projectile would land on the floor. A very nice job was done by all, even when the challenge was turned around and people had to figure out how to strike a target by manipulating the launch velocity of the projectile. We'll talk about horizontally-launched projectiles in class tomorrow, after going over the vector homework, so you can use that discussion to help with your lab write up that is due on Thursday.