Science Activity: Physics Tug of War

By: Owen Hawkridge

Curriculum Fit:

• Science 10: Unit Four: Concept Four
• “the amount of useful energy diminishes during any energy transformation”

Materials:

• Large, heavy rope
• For example, a car tow rope

Description:

Depending on the length of your rope, 1-3 students hold on to each end of the rope. Students are instructed to pull as hard as they can on the ends of the rope (without pulling each other over). One student is asked to try to deflect the rope by pulling down at the centre (for added effect choose a “smaller” student and have them use only one hand). No matter how hard the people at the ends pull, the middle person will always be able to cause a dip in the rope with minimal force.

Explanation:

Sin (Angle of deflection) = X / 500 N So X=87 N. 500 Newtons of force directed almost horizontally, when broken down into its component forces, produces only 87 N of upward force. The middle person only needs to exert 174 N (87N X 2) to deflect the rope.

Owen Hawkridge

Dr. Nocente

12, February 2002