Park Physics with Sean Lally - 2017-2018

In these problems you will need the formulas for the period of a simple pendulum AND the rearranged version (solving for L) we worked out in class. 1.  What is the period of a 1-m long pendulum?  Do you remember the historical significance of this particular length of pendulum?  If not, look back in your notes from the first few days of class. 2.  If you want a Grandfather clock to swing with a 1-second period, how long should the pendulum be inside of it? 3.  Calculate the experimental length of the giant swing, assuming that someone took 2.8 seconds to swing from rest on the platform to the opposite side of the swing (on the left).

1.  Graph period of ONE swing (T, in seconds) vs. length (L, in meters).  T will be on y-axis and L will be on x-axis.  Make certain that length is converted to meters (if you used cm). 2.  Print out graph. 3.  Make a third column of data - square root of each length measurement (in meters). 4.  Think/write about this:  What makes a simple pendulum "simple"?  What is assumed to be true about the simple pendulum? 5.  If you have the video from the giant swing, try to determine the period of one oscillation (one complete swing of the person).  We are going to try to compare theoretical pendulums to the giant swing in our next class.

Review the notes on the blog (2 posts ago) and try these questions and problems (similar to what we did in class today, Monday 4/2). 1.  Give an example of 2 different conservation laws. 2.  What is the mathematical definition of momentum? 3.  What is the conservation of momentum, and when do we think about it (under what specific circumstances)? 4.  A 300-g cart moving at 40 cm/s hits another 300-g at rest.  Friction is very low.  What do you expect will happen exactly?  Give numbers if possible. 5.  A 60-kg figure skater skating at 8 m/s collides directly with a 40-kg skater initially at rest.  Friction is very low and the two become intertwined on the ice.  Calculate the speed of the two of them together after the collision.  (Hint:  First find the momentum of the 60-kg skater, and then use conservation of momentum to solve for the final speed of the two together.  This is like the velcro cart collisions.) 6.  (Challenge problem)  A 2-kg ball is traveling at 4 m/s and it