Table of Mechanics

Mechanics (1G): Newton's Second Law

Mechanics (1J): Statics of Rigid Bodies

Lecture Demonstrations

Newton's Third Law

PIRA classification 1H

Third law: The mutual forces of action and reaction between two bodies are equal, opposite, and collinear.

15 Demonstrations listed of which 11 are grayed out.

Grayed out demonstrations are not available or within our archive and are under consideration to be added.

1H10. Action and Reaction


Demonstration Name




Push Me, Pull Me Cart


Two people on roller carts each hold on to opposite ends of a wooden rod. They each push or pull on the rod causing a reaction on the opposite person.


Carts and Ropes

Stand on a cart holding a rope passing over a pulley to a weight slightly less than static friction, then pull the rope.


Reaction Gliders

Cut or Burn a string holding a compressed spring between two air gliders.


Newton's Sailboat

A battery powered fan and sail can be mounted on a air track cart. Three cases are demonstrated: 1) sail attached, fan not attached; 2) both sail and fan attached; 3) fan attached, no sail. See TPT 10(4), 208.


Newton's Sailboat

A balloon provides an air source on one cart, a sail is mounted on another cart. Hold each stationary in turn. See TPT 10(9), 488.


Helicopter Rotor (Broken)

A symmetric propeller deflects air down, causing upward lift.


Cannon Car

A small brass cannon mounted on one car fires a bullet into a wood block on another of equal mass. A string tying the carts together will result in no motion. See Sutton M-122.



The major motion of blood pulling then ejected by the heart is longitudinal and according to Newton's 3rd Law the force exerted on the blood by the heart can be see with this horizontal table on rollers and shows an equal and opposite force on the body by the blood as it's being pumped, which is parallel to the spine.

1H11. Recoil


Demonstration Name




Floor Cart and Medicine Ball

Stand on a roller cart and throw a heavy medicine ball or Styrofoam ball.


Stool on a Conveyor

Throw a ball sideways while on a stool mounted on a conveyor.


Tennis Ball Cannon

A cannon on wheels shoots a tennis ball.


Liquid Nitrogen Cannon

A homemade aluminum cannon with a 3" bore diameter and nearly 34" bore length is mounted on two 24" bicycle wheels and shoots either rubber stoppers or bottles filled with sand to show recoil. The only propellant is the pressure buildup from the liquid nitrogen transitioning from liquid to gas.


Liquid air gun

Liquid air in a bent test tube shoots a cork when the escape valve is closed.


Ballistic Gun

Shoot a spring loaded bifilar suspended gun. Measure the muzzle velocity by range and the recoil by adjacent scale.


Open Cannon

A hole in the back of a rail mounted gun allows the gasses to escape or not to show the difference on recoil.


Bent Gun

A spring loaded gun firing a steel ball has a barrel bent 90 degrees to show recoil opposite the exit direction instead of the firing direction.

Table of Mechanics

Mechanics (1G): Newton's Second Law

Mechanics (1J): Statistics of Rigid Bodies

Lecture Demonstrations



fw: Newtons3RDLaw (last edited 2018-07-18 16:42:34 by srnarf)