What We Have Done In Physics So Far

AP Physics has been one of my favorite classes.  We learn a lot in an interactive way by writing all of our work on a white board, talking over it with a class, learn from all of our tests then use the results in an interactive way.  We have landed bean bags in small buggy cars, had a "police chase" with a constant velocity buggy car and an increasing velocity fan car, used a cannon to shoot a ball and catch it in a can, then did the same thing from different heights, and even launched tennis balls with a self made trebuchet.

Most of everything we did revolved around an object in free fall, or the force of the earth on an object.  For instance, if an object on the ground is shot up with a certain velocity and if an object at position off the ground, we could tell you how long it took for each object to hit the ground, which one is in the air for longer, which one goes higher, when they have the same speed and why when they have the same speed it doesn't mean that they have the same velocity.

We have also done a lot with horizontal speed like with a metaphorical boat crossing a river.  Our class now has the knowledge that if we are given the speed of the boat and the speed of the current, we can find at what angle the boat must be positioned compared to the river to make it to a spot on the other side, how long it would take to get there, and what the speed of the boat is if it goes straight across or what it might look like from a creature in the river.  This information can be very useful in the real world and can help work at problems people may have if they need to drop a bowling ball from a tall building but don't know how long it will take or if they have a boat, a river, and a protractor and need to find out where to go to make it all the way across the river.  I look forward to learning even more in this class.

Drop Height vs. Fall Time Blog

Another day, another lab in physics.  It has been a fun class so far learning how bikes work and why people don't know how they work even if they use it every day.  Just stuff like this every now and then keeps me focused and interested in the class.  Anyways our most recent lab was all about when we drop a ball how long it takes until it hits the ground.  My group predicted that it would be a root relationship with height on the x axis and time on the y axis, and it was.  To be exact we found the equation to be T=0.3587H^1/2.

This part was the relatively boring part, but now using the equation we got, we were able to calculate what we thought the time would be if we dropped a bean bag from 3 floors up on an X on the ground.  We then used a buggy, found the speed of the buggy and started it 2 meters away from the X.  Using the speed we calculated and the time it takes for the bag to fall from that height we found the point that where the buggy crosses where we can drop the bag and hopefully get them both to hit the X at the same time and land the bag in the buggy.  Unfortunately, it hit and bounced off for us, but it was close.

Ball Bounce Blog

Well, here it is, the first blog of the year.  School has started again, and physics is as fun as ever.  This year my teacher opened up by having everyone juggle and recite a 100 or more word speech (but not at the same time).  This was probably the most important lesson he could have taught us, right off the bat.  We also learned a lot about my teacher's son's rock climbing experience and the power of chicken nuggets.
Moving on, we did a lab in class about the bounce of a ball and how high it goes compared to the height when it is dropped.  My group predicted that it was linear and proportional.  When we tested it out we found that it in fact was.  However, there was one slight hiccup.  We didn't know if when we drop the ball we measure the drop height at the bottom of the ball or the top.  We did the top but that ended up being the wrong way to do it.  It was okay because that made such little difference in the results that we were fine.  In the end we found that for every meter added to the drop height, there are .71 meters added to the bounce height.  Other groups got different results and as a class we collectively decided that it is always a proportion, but that proportion depends on what is being dropped.  A super ball will have a high proportion close to one, but something else may be close to zero.  This is now called the bounce coefficient.