Ballistic Pendulum II

We will now check your calculations of the ballistic pendulum. Let's use the medium-range setting of the gun.

  1. Measure the distance H from the floor to the top of your table, and the distance h from the tabletop to the ball as it sits in the catapult's muzzle. Note the uncertainty in each.
  2. Determine the total vertical distance between the ball and the floor, and its uncertainty.
  3. Calculate the distance the ball should fly horizontally, based on this vertical distance and the speed of the ball you determined last week. Use the velocity you computed for the medium-range setting.
  4. Compute the uncertainty in this distance, using both the uncertainty in the muzzle velocity of the ball, and the uncertainty in the height above the floor.

At this point, call an instructor over. Show your work. If it all looks good, you'll be ready for action:

  1. you will be given a cardboard box; place the box on the floor so that your predicted position falls in its middle
  2. place a sheet of carbon paper in the box, and cover it with a sheet of blank ordinary paper
  3. tape the paper into the box, and the box onto the floor
  4. on the sheet of paper, mark your predicted location, and show the range of distances given by your uncertainty analysis

After firing your catapult five times, remove the sheet of white paper from the cardboard box. Staple it together with your other work -- measurements and calculations -- and place it all into your folder.