Equal & Opposite Thrust in Aircraft: You’re a Pushover!
Figure skaters demonstrating Newton's third law of motion.Copyright 2006 Benjamin Crowell, Wikimedia Commons http://commons.wikimedia.org/wiki/File:Skaters_showing_newtons_third_law.svg
Through this activity, Newton's third law of motion is demonstrated, which is the physical law that governs thrust in aircraft. Guided by a worksheet, students do several activities —pushing on walls, releasing air from balloons—that show that for every action there is an equal and opposite reaction. They also calculate the missing mass or acceleration based on the the third law of motion equation: mass of object 1 x acceleration of object 1 = mass of object 2 x acceleration of object 2. They relate their understanding of the third law of motion and thrust to crashed cars and airplane movement.
Engineers apply their understanding of scientific principles, such as Newton's laws of motion and mathematics to design, analyze and improve their inventions. Engineers use algebra and basic math skills to determine exact values for variables such as velocity, temperature, acceleration, energy and mass. Using these real measurements and calculations enables engineers to design efficient, safe and successful aircraft.
After this activity, students should be able to:
- Explain that two objects pushing off of each other experience the same force.
- Relate the amount of air pressure with acceleration.
- Use algebraic methods to describe Newton's third law of motion.