2) Mechanics

a) Basic mechanics

I) General Things

                          Shows uniform acceleration, velocity and distance Shows constant acceleration Shows constant velocity, friction less surface, uniform acceleration when inclined, use
light gates or stopwatches to time motion, shows center of gravity, shows momentum Collisions. Shows friction less motion where students can ride basically a small hovercraft Roll a small cart on top of a larger cart to discuss the relative velocity between carts Pull across table with force scale to show static/kinetic friction Shows mass on an incline and friction coefficient. Shows vector components of forces on a mass Shows Newton's third law, can be pulled with force scale for Newton's second law The cart has a fan to push it forward and a sail that can be added that prevents it from
moving. Shows F=MA by pulling a person (or weight) across the floor or set up a tug of war Shows the tension in a tightly stretched wire that has a mass hanging in the middle. Shows shear strain on a foam cube. ii) Simple Machines


iii) Center of Gravity and Center of Mass

Shows Forces in Equilibrium with a door suspended without hinges. (I need an hour's
notice) Shows a stable and unstable tower when the center of gravity is no longer over the base. Finds center of mass for a non uniform shape (Also can shoe Torque Arm). Shows parabolic motion of the center of mass as a Florida shaped object is tossed. Toy that spins preferentially in one direction. Uses its shape to direct a component
of its weight to cause the spinning. Find the center of gravity by sliding your fingers underneath it until they meet. Hangs oddly over the edge of a table. Disc that wobbles when rotated about its center. But it is stable when rotated off axis. Balance 12 nails on one standing nail.                            Hangs oddly off edge of table. Cart and pendulum masses oscillate around center of mass. Wooden plank and cylinder to stand on for balancing.                            Cone appears to roll uphill but the center off mass is actually falling,

iv) Projectile Motion

Drops one ball vertically and projects one horizontally at the same time. Cart rolls across table and shoots a ball vertically and then catches it. Blowgun dart shoots a falling target. This is a great demo but I need an Hours notice to do
it. Measures muzzle velocity for a projectile problem. Simple, safe, way to show range equation by shooting darts at various angles.
 
  v) Gravity Experiments Drop the penny and feather in a vacuum and in air. Water streams out small holes in the side of the cup until it is dropped. Simulates
weightlessness in a free falling object. Shows square ratio of distances for falling objects. The ball strikes the ground in equal time
separations. Calculates gravity by measuring the time for a ball to drop 2 meters. Inclined board where the end of the board moves faster than gravity to catch a ball. Drops balls of different densities into water t show terminal velocities as they sink. vi) Inertia Heavy lead ball suspended by string. If you pull fast the bottom string breaks, pull slow
and the top string breaks. Pull cloth from underneath dishes.                            Shows how to measure mass in a weightless environment. Lay between two nail beds and have concrete block broken on your chest. It's very
impressive and not as dangerous as it might seem. Shows inertia and force per unit area. b)Rotational Motion and Torque Spheres, Solid and Ring disks, etc... for comparing Moment of inertia from bodies
of different shapes. Two equal mass batons where the mass is distributed differently. The batons are held
in the middle and pivoted back and forth to feel difference in inertia. Disk that either rolls forward or backwards depending on the angle of that pulls it. Shows comparison between linear and angular measure. Tennis ball or foam ball on a string for circular motion and centripetal force. Can be used to measure centripetal force using a weight hanging down from the handle. Two water bottles on a turntable with a floating ball and a sinking ball suspended within
each bottle. As it's turned the floating balls lean inwards and the sinking balls lean
outwards.                            Water stays in bucket as you rotate in a vertical circle. Balance a penny on the end of a coat hanger and rotate in a vertical circle. Shows precession when used as a large gyroscope or with the rotating chair. Shows angular velocity on a solid disk. Chalk erasers are placed on it at different radii
And fly off at different rotation speeds.                           Meter stick with masses suspended from it to demonstrate torque. Small torque meter sticks on stands. Can rolls across the ground and then rolls back to you on stored energy.


c) Energy and Simple Harmonic Motion

Heavy Ball suspended by rope from the ceiling for gravity measurement, SHM and
Conservation of energy. Shows simple harmonic motion in rotation. Shows a comparison between a ring oscillating and a ball on a string. Either a W or U shaped track to show conservation of a potential well. Shows energy conservation, minimum velocity to complete loop and vertical circle. A race between two balls as they move between the same change in potential energy.
One follows a straight track and the other follows a longer curved track.
The curved track ball finishes first due to higher kinetic energy. Shows F=kX and simple harmonic motion. Projects the shadow of a rotating peg and a mass on a spring.
Compares linear to circular motion. Two springs tied together with a mass on the bottom.
When the middle string is cut leaving only a string from the support to the top of
the bottom spring and a string from the bottom of the top string to the mass the total
length gets suprisingly shorter. Drop a superball and a dud ball that doesn't bounce. Provides a measurement system to check balls bounce and conservation of PE. Shows shear strain on a foam cube. d) Momentum Collide carts of various masses to see linear momentum in action. 2 X 3 Air table to show 2D collisions similar to the linear collisions on the 3 m air track. Shows recoil of a gun when a firecracker is exploded between cans. Shows conservation of momentum using five balls colliding. Basically a fun Newton's ball toy. Drop a basketball with a foam ball placed on the top.
The foam ball shoots off quickly when they hit the ground. A block is hit by a blow dart and tips over in an elastic collision but not in inelastic. Shotgun shell is fired to project a bullet into a catcher.
A spark recorder measures the height of the recoiling catcher and muzzle velocity can
be calculated. Shows relation of mass position to moment of inertia and resulting angular velocity when
a constant force is applied. Students can sit in chair and experience conservation of angular momentum.
It can also be used with the bicycle wheel gyroscope. Shows a 2D collision, but the apparatus is small and not well suited for lecture. Show collisions between rolling balls on a straight track. (air track does a better job)