## Car Physics: Understanding Newton's Laws of Motion

Sir Isaac Newton’s three laws of motion are manifested in almost every activity which goes on in daily life. From a running car to a bird flying, Newton’s three laws of motion are ubiquitous. In fact, more than 99 percent of activities in the physical world are governed by these laws. Newton proposed the three laws of motion to explain how planetary motions work, how any object that has mass responds to an external force, and several other significant phenomena.

## First Law of Motion

The first law of motion defines two facets of motion. The first speculates the behavior of objects which are stationary while the second predicts a moving object’s behavior. The first law says that “a body remains at rest or moves in a straight line of constant velocity as long as no external forces act on it”. To illustrate, a car will remain in motion unless an external force by means of a brake is applied on it.

• Role of Forces: The Boston University Physics Department explains how a force influences the motion of objects and proves the laws of motion in practical context.

## Second Law of Motion

Newton's second law of motion predicts the behavior of an object in which the forces which acts on an object is not balanced. The second law states that “a body acted on by a force will accelerate such that force equals mass times acceleration” (F=ma). Hence, the net force determines the acceleration of the object. To illustrate, as a car gains more acceleration (by means of the accelerator), the more force it will exert when it collides against a tree or a physical structure.

• Galileo’s Ideas: The article explains how Newton probed the findings of Galileo, concentrating mainly on acceleration of moving objects.
• Mechanisms: Describes various physical principles and explores the concepts of torque, momentum, and energy.
• Causes of Motion: Provides explanation for the way objects behave when in motion and when at rest.

## Third Law of Motion

The third law states “for every action there is an equal and opposite reaction”. It refers to the conservation of energy. The third law also mentions the contribution of force. A force is essentially a pull or push on a particular object which is a result of interaction with another object. In case of a car accident, the force with which the car crashes into the tree would result in the tree exerting the same amount of force on the bonnet, and damage it. The directions of the forces are opposite.

• Third Law of Motion: Physical Science Activities Manual by the University of Tennessee at Martin demonstrates the Third law of motion using a balloon race.

## Teacher Resources

• Force & Motion: An activity page providing teachers with projects to be done in classroom.
• Practical Exercises: Discussion questions posted by Eastern Illinois University. The page provides some exercises for teachers to show to the students.
• Physical Science: Paper by National Science Foundation, Drexel University, providing worksheets and activity list to be performed by students.
• Lab and Activities: Labs and activities by Department of Physics, California State University, providing practical applications of the three laws of motion.
• Newton's Third Law: Teaching resource compiled by Jerri Chavis and Langston Hughes, providing individual activities for students.
• Newton’s First Law: The page on NASA website showing how the first law of motion is applied to an airplane.
• Newton’s Laws of Motion: Faculty resource by Fayetteville State University offering a classroom experiment based on Newton’s Laws of motion.
• Force & Motion: Come here to learn about how force and motion works according to Newton’s laws.
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