Mechanics

Zoom image: Angular momentum A wheel is spun to a high angular velocity. The instructor holds the spinning wheel and sits on a stool that is free to rotate. As the instructor flips the wheel sideways, the stool will spin the opposite way to conserve angular momentum. A variation of the demo can be done where the instructor holds weights with open arms, and spins around in the stool. When weights are pulled in close, the instructor's moment of inertia will be less. The stool will spin faster.

Angular momentum

Zoom image: Ballistic pendulum A ballistic pendulum can be used to demonstrate properties of momentum and energy.

Ballistic pendulum

Zoom image: Circular motion 1 A ball with a string attached is swung around in a circle. When the instructor let's the string go, the ball will start moving in a linear trajectory.

Circular motion 1

Zoom image: Fan cart with sail A sail is attached to a fan cart. When the fan is switched on, the cart will not move since action and reaction forces cancel each other.

Fan cart with sail

Zoom image: Gyroscope 2 Various small gyroscopes can be used to demonstrate precession and conservation of angular momentum.

Gyroscope 2

Zoom image: Inertial frames A cart with a vertical ball launcher travels across a track. When it passes a trigger, a ball is launched vertically relative to the cart. The ball will travel straight up and down in the cart's frame of reference, but in an arc when observed in the lab's frame of reference. Since the cart and the ball have the same horizontal velocity when the ball is launched, the ball will land back on the cart despite its motion during the flight.

Inertial frames

Zoom image: Moment of inertia 1 4 weights are located on rods at adjustable distances from the center of a rotating mount. A small weight attached to a string is released to apply constant torque to the system. When the weights are positioned close to the center, the system will turn faster due to having less moment of inertia.

Moment of inertia 1

Zoom image: Pendulums Pendulums with various lengths are swung to show the difference in their periods of oscillation.

Pendulums

Zoom image: School bus on incline A school bus is connected to force sensors parallel and perpendicular to the ramp it is on, demonstrating the components of force for an object on an incline.

School bus on incline

Zoom image: Balancing blocks 4 wooden blocks are balanced on the edge of a table, with approximately 1/8, 1/6, 1/4 and 1/2 of their length over the edge respectively. The wooden block on top will be completely off the edge of the table.

Balancing blocks

Zoom image: Center of gravity 1 A cylinder and a double cone are placed on a triangular ramp. The two objects will roll in opposite directions. This is because to achieve the lowest potential energy, the center of mass of an object must be at its lowest point. The cylinder rolls down the incline of the ramp, but the double cone moves in the direction where the triangular ramp gets wider in order to lower its center of mass.

Center of gravity 1

Zoom image: Circular motion 2 An accelerometer is swung around on a circle by a 12 V DC electric motor. The accelerometer has two positions on the set-up; at r= 5 cm and r= 10 cm. The centripetal accelerations at each location can be read through a Bluetooth connection.

Circular motion 2

Zoom image: Force table Weights are hung on four pulleys around the force table to exert forces on the center ring. The angles of the forces can be adjusted. When the net force is zero, the ring will float in equilibrium.

Force table

Zoom image: Hoberman sphere A Hoberman sphere can be used to demonstrate conservation of angular momentum. After giving the sphere a spin, pull the attached string to shrink its size. The sphere will start spinning faster.

Hoberman sphere

Zoom image: Lever balance Weights can be added to different positions on a lever balance with a pivot at its center. When clockwise and counter-clockwise torques are equal, the lever balance will be in equilibrium.

Lever balance

Zoom image: Moment of inertia 2 Various objects with different masses and shapes, and therefore different moments of inertia, can be rolled down two identical ramps. The time it takes each object to roll down is different. Some of the objects have the same masses, and can be raced to show that the object with the least moment of inertia takes shortest time to roll down.

Moment of inertia 2

Zoom image: Projectile launcher A ball can be launched at various angles with the projectile launcher to demonstrate motion in 1 and 2 dimensions.

Projectile launcher

Zoom image: Softball pendulum A softball is hung from a tall stand placed on a lecture hall desk. The instructor pulls the ball to his/her nose and lets go. The ball will swing back just short of the instructor's nose.

Softball pendulum

Zoom image: Ball on V-track A track with two sides at different angles to the horizontal forms a valley. A ball will roll down one side and up to an equal height on the other.

Ball on V-track

Zoom image: Center of gravity 2 Pencils with attached wires can be balanced on their tips. The balancing bird will remain in balance on its beak. A set of bolas thrown in the air will rotate around their center of gravity.

Center of gravity 2

Zoom image: Collision carts Vernier collision carts can be collided on a track to show various types of collisions. The carts have Velcro pads on one side, and (repelling) magnets on the other. A fan can be attached to the carts to apply constant force.

Collision carts

Zoom image: Gyroscope 1 A gyroscope is spun and balanced on a stand to show precession and conservation of angular momentum.

Gyroscope 1

Zoom image: Hooke's law Washers are added to the top of a spring. Spring compression varies linearly with the number of washers or force on the spring, demonstrating Hooke's law.

Hooke's law

Zoom image: Loop the loop A track forms a loop-the-loop. A ball released above a certain height on the track will roll down and complete the loop.

Loop the loop

Zoom image: Newton's craddle Balls with equal masses hang from strings in a row. When a ball from one end is pulled and released, it will transfer its momentum along the line of balls, causing the ball on the opposite end to bounce out.

Newton's craddle

Zoom image: Roman arch A Roman arch made of small wooden blocks can be used to demonstrate equilibrium.

Roman arch

Zoom image: Tracks that transition to horizontal Ping pong balls are rolled down various tracks that transition to horizontal. The balls will reach the edge of tracks at different times, but with the same velocity. They will all land in the basket on the floor.

Tracks that transition to horizontal