state 2 application of third law of motion.
Answers
Students are introduced to Newton's third law of motion: For every action, there is an equal and opposite reaction. They practice identifying action-reaction force pairs for a variety of real-world examples, and draw and explain simplified free-body diagram vectors (arrows) of force, velocity and acceleration for them. They also learn that engineers apply Newton's third law and an understanding of reaction forces when designing a wide range of creations, from rockets and aircraft to door knobs, rifles and medicine delivery systems. This lesson is the third in a series of three lessons intended to be taught prior to a culminating associated activity to complete the unit.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).
Engineering Connection
Consider the apple, which according to folklore, fell on Isaac Newton's head and sparked his thoughts on gravity and motion. Gravity applies a downward force on the apple's stem, and the stem applies an equal and opposite force upwards to keep the apple suspended. When the stem became too weak to apply an equally strong reaction force, the apple plunged downward toward his head.
Examples of Newton's third law of motion are ubiquitous in everyday life. For example, when you jump, your legs apply a force to the ground, and the ground applies and equal and opposite reaction force that propels you into the air. Engineers apply Newton's third law when designing rockets and other projectile devices. During launch, the burning fuel exerts a downward force, and the reaction force pushes the rocket into the air. In space, the rocket applies its rear thrusters to move forward, which provides another example of how engineers take advantage of reaction forces in their designs.
Learning Objectives
After this lesson, students should be able to:
Identify action-reaction force pairs.
Draw and explain simplified free-body diagrams showing action-reaction pairs.
State and explain Newton's third law.
ANSURE
Examples of Newton's third law of motion are ubiquitous in everyday life. For example, when you jump, your legs apply a force to the ground, and the ground applies and equal and opposite reaction force that propels you into the air. Engineers apply Newton's third law when designing rockets and other projectile devices.