Physics Demo Number: 068

Approximate Run Time: 10 min

Folding Wheel Chair For Demonstrating Newton's 3rd Law or Vector Sum of Forces

Demo Description

Demonstrate action/reaction forces by pulling a rope while seated in a chair. Sit in folding wheel chair and propel yourself backwards by pushing forwards on a fixed lecture table or on the wall .

Scientific Principles

Newton's 3rd Law

Equipment & Set Up

• Wheel Chair

• Yellow Rope

Equipment Location

• The chair resides in the little room to right of Faculty Desk.

• The yellow rope is normally found in Kit (068) on [F-1-3].

1

2

Instructions

One may sit in the pictured chair and push on something such as the fixed lecture table to show that the resulting push back on the chair system by the lecture table will move the chair system  in a direction opposite to that of your applied push.

One may also use the yellow rope seen in photo 2 and anchor one end of it to a fixed point.

Then while sitting in the wheel chair,  one may pull on the other end of the rope.

The ensuing motion will be movement of the wheel chair system towards the fixed point.

One may enlist the help of two assistants to pull on the ends of the rope while the lecturer holds the middle of the rope to show vector addition on a large scale.

Utilizing an office chair and large rope, one may secure the middle of the rope as shown, or simply sit in the chair.

Have two assistants (who stand on two of the vertices of a large isosceles triangle whose third vertex is under the chair) pull on their ends of the rope while you hold the center of the rope to exhibit vector addition of forces on a large scale.

Writeup created by David A. Burba

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