Mechanics

M-K1 : Propeller Cart

Unit

Conservation of Momentum

Purpose

Illustrate the concepts of velocity and acceleration for straight-line motion (with constant acceleration).

Equipment

  1. Electric motor-driven cart with a propeller (CENCO)
  2. Detachable screen
  3. Two AAA batteries

Suggestions

Screen out

  1. With motor "off" illustrate friction: vo > 0, a > 0; vo < 0, a > 0
  2. With motor "on" illustrate: vo > 0, a < 0; vo < 0, a < 0
  3. Can it be: vo = 0, a > 0
  4. Can it be: vo > 0, a = 0
  5. What will happen if the screen is attached?

Discussion

  1. V > 0
  2. V = 0

M-K2 : Mariott Tube (comp. M-F7)

Unit

Bernoulli's Principle (Kinematics in 2-dim)

Purpose

Interesting evidence of the Bernoulli's Principle

Equipment

  1. Mariott Tube: A cylinder with three holes (stoppers)
  2. Base pan & stand for the tube
  3. Pitcher for water

Suggestions

Holes are numbered 1-3 from bottom to top.

  1. With 1 and 2 open, ask for prediction and run
  2. With all open, ask for prediction and run
  3. Explain

Discussion

  1. Equipment and set up
  2. Filling the tube to the brim
  3. Stoppers removed, liquid level continuously maintained
  4. Close-up of the streams: top and bottom arrive at the same point, middle stream goes farther

M-K3a : Falling Monkey (I)

Unit

Kinematics in 2 dim

Purpose

Illustrate the seperation of vertical and horizontal motion for projectiles

Equipment

  1. Air gun with magnetic release
  2. Electromagnet suspended on a stand
  3. Can - the target ("monkey")
  4. Several bullets (metal balls)
  5. One 9V battery and wires

Discussion

  1. Equipment and set-up
  2. Ejection
  3. Collision

M-K3b : Falling Monkey (Uchida)

Unit

Projectile Motion

Purpose

To demonstrate the independence of x-and y-motion

Equipment

  1. Gun assembly with a 9V round battery
  2. C-Clamp to attach the gun to a table
  3. The red target with a security string
  4. Stand for target assembly
  5. Electro-magnet to suspend target
  6. Small white ball
  7. Telescopic sight

Suggestions

  1. Aim the gun at the target using the telescopic sight
  2. Remove the telescope and cock the gun using the transparent plastic block.
  3. Suspend the target (tuck away the string)
  4. Remove the block while holding the launcher
  5. Adjust the launcher to the desired stretch and release.

Discussion

In a large classroom demo, Falling Monkey I is a more effective demo. In particular, the collision is apparent even for people sitting far away due to the sound of impact.

In order with pictures from left to right.

  1. Equipment
  2. Cocking the gun
  3. With the block in place, the ball is placed in the gun
  4. Set-up complete with the target suspended by the electro-magnet
  5. Just before collision
  6. Collision

听

M-K4 : Inertia

Unit

Inertia

Purpose

To demonstrate the concept of inertia

Equipment

  1. Inertia Demo
  2. 3x5 Index Card
  3. Small ball

Suggestions

  1. Set up the index card such that it is perpendicular to and centered on the bar.
  2. Set the bar up such that it is centered on the hook.

M-K5 : Ball and String (I)

Unit

Kinematics in 2 dim, circular motion

Purpose

  1. Illustrate various kinds of circular motion
  2. Consider instantaneous velocity and acceleration in each case

Equipment

A ball with a long string attached

Suggestions

Demonstrate circular motion

  1. Whirling in horizontal (Note that the string itself cannot be horizontal!)
  2. Whirling in vertical (Note that the speed cannot be constant!)
  3. Pendulum motion
  4. Discuss whether the speed and the magnitude of acceleration change or remain constant in each case 1-3
  5. Discuss the change in direction of velocity and acceleration in each case 1-3

Discussion

Requires a full discussion of circular motion, including tangential and perpendicular (radial, centripetal) acceleration

M-K6 : Ballistic Car (I)

Unit

Projectile motion

Purpose

Illustrate that the vertical and horizontal motions of a projectile are independent of each other

Equipment

  1. Free-rolling ballistic car (CENCO)
  2. Shooting ball, pin with string

Suggestions

There are two openings for the pin and two holes in the piston. Try all four combinations. Best effect is obtained with the maximum piston force, and as small.

M-K7 : Ballistic Car (Pasco)

UNIT

Projectile Motion

Purpose

Illustrate:

  1. Independence of the vertical and horizontal motions
  2. Vector nature of acceleration
  3. Accelertation in inclined-plane motion
  4. "Bombing run" strategy

Equipment

  1. Ballistic car accessory (Pasco,听(requires 9V battery)) 听听听 听听听 听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听听听 听
  2. Drop rod accessory (Pasco)
  3. Pasco 1m track
  4. A stand to raise one side of the track
  5. Pulley with clamp, string, and weight

M-K8 : Ballistic Pendulum

Unit

Momentum and mechanical energy and conservation

Purpose

To make an initial velocity calculation using the momentum equations

Equipment

Cenco Ballistic Pendulum

Suggestions

Vary the launch speed by adjusting the screw at the end of the gun

Discussion

  1. Equipment
  2. End position

M-K9 : Projectile Launcher

Unit

Projectile Motion

Purpose

To explore the effect of angle and initial speed on the range of a projectile

Equipment

  1. Projectile launcher
  2. Projectiles
  3. Meter Stick

Suggestions

  1. Balls can be launched at any angle from 0-90 degrees, use the plumb bob on the side to set the angle.
  2. There are three different ranges which are 2.5 meters, 5 meters, and 9 meters.
  3. There are sights for aiming the projectile launcher that can be viewed from the back.
  4. Photogates can be attached to measure muzzle speed.
  5. For stability, launcher should be clamped to a table

M-K10 : Gravitational Torsion Balance

UNIT

Gravitation

Purpose

To show the gravitational force between a large and a small object

Equipment

  1. Support base with leveling Feet
  2. 1.5 kg lead balls (2)
  3. Gravitational Torsion Balance
  4. plastic plate
  5. replacement torsion ribbon
  6. Laser light source (PASCO OS-9171 He-Ne Laser)
  7. Meter stick

Suggestions

Experiment is not suitable for classroom demonstration, however equipment is of interest for historical reasons.

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