What Is Newton's Second Law?
Newton's laws of motion explain the movement of everyday objects and are important to engineers who design machines, structures and products for our safety and enjoyment.Copyright Microsoft Corporation, One Microsoft Way, Redmond, WA 98052-6399 USA. All rights reserved. http://office.microsoft.com/en-us/images/results.aspx?qu=construction&ex=1#ai:MP900439313|mt:2|
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Students are introduced to Newton's second law of motion: force = mass x acceleration. After a review of force, types of forces and Newton's first law, Newton's second law of motion is presented. Both the mathematical equation and physical examples are discussed, including Atwood's Machine to illustrate the principle. Students come to understand that an object's acceleration depends on its mass and the strength of the unbalanced force acting upon it. They also learn that Newton's second law is commonly used by engineers as they design machines, structures and products, everything from towers and bridges to bicycles, cribs and pinball machines. This lesson is the second in a series of three lessons that are intended to be taught as a unit.
Newton's second law of motion provides the foundation for much of the mathematics in engineering mechanics. In the study of dynamics, engineers apply Newton's second law to predict the motion of an object experiencing a net force. Using the equation F = ma, engineers can model the position, velocity and acceleration of an object, or they can measure these values to learn about the forces acting on the object. In the field of statics, engineers use Newton's second law to calculate forces acting upon stationary objects. Because a non-moving object's acceleration is zero, the forces acting on the object must sum to zero. For example, in designing structures, engineers apply Newton's second law in calculating the forces acting on joints in the framework of buildings and bridges.
After this lesson, students should be able to:
- State Newton's second law and explain what it means.
- Explain that force is measured in Newtons, and that mass is measured in kilograms.
- Distinguish between mass and weight.
- Use Newton's second law to compare the amount of force required to move objects of varying masses.