Ballistic Pendulum II
We will now check your calculations of
the ballistic pendulum.
Let's use the medium-range setting
of the gun.
- 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.
- Determine the total vertical distance between the
ball and the floor, and its uncertainty.
- 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.
- 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:
- you will be given a cardboard box; place the box
on the floor so that your predicted position falls in its
middle
- place a sheet of carbon paper in the box, and cover it with a sheet
of blank ordinary paper
- tape the paper into the box, and the box onto the floor
- 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.