Bell Work 11/5/2014 Describe static, sliding, rolling, and fluid friction. Describe the differences between balanced and unbalanced forces.

Newton’s Laws of Motion

Sir Isaac Newton’s Contributions Calculus Light is composed of rainbow colors Reflecting Telescope Laws of Motion Theory of Gravitation

Newton’s First Law (law of inertia) An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force.

Objects at Rest Objects at rest tend to stay at rest unless acted upon by a force. [push or pull] Newton described this tendency as inertia. Inertia can be described as the tendency of an object to keep doing whatever it is doing.

If objects in motion tend to stay in motion, why don’t moving objects keep moving forever? Things don’t keep moving forever because there’s almost always an unbalanced force acting upon them. A book sliding across a table slows down and stops because of the force of friction. If you throw a ball upwards it will eventually slow down and fall because of the force of gravity.

Newton’s First Law (law of inertia) INERTIA is a property of an object that describes how ______________________ the motion of the object more _____ means more ____ much it will resist change to mass inertia

Newton’s 1st Law of Motion Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

Newton’s 1st Law Once airborne, unless acted on by an unbalanced force (gravity and air – fluid friction) it would never stop!

Newton’s Second Law Force equals mass times acceleration. F = ma

Newton’s 2nd Law of Motion Force = Mass x Acceleration Force is measured in newtons (N) ACCELERATION of GRAVITY(Earth) = 9.8 m/s2 Weight (force) = mass x gravity (Earth) Moon’s gravity is 1/6 of the Earth’s If you weigh 420 N on earth, what will you weigh on the Moon?

Newton’s Second Law WEIGHT is a measure of the force of ________ on the mass of an object. measured in __________ gravity Newtons

Centripetal Force A force that pulls an object moving in a circular path toward the center of its path. The force that keeps the female skater moving in a circle is the pull exerted by her partner.

Newton’s Third Law of Motion When one object exerts a force on another object, the second object exerts an equal and opposite force on the first object.

YOUR TURN: Draw a situation in which a force pair acts YOUR TURN: Draw a situation in which a force pair acts. Use arrows to label the action and reaction forces. Be ready to present.

Summary of Newton’s 3 Laws: 1. If you don’t push it, it won’t move 2 Summary of Newton’s 3 Laws: 1. If you don’t push it, it won’t move 2. If you push it, it will move 3. If you push it, it pushes back

Define Newton’s First Law of Motion Newton’s Second Law of Motion Inertia Gravity Weight Centripetal force Newton’s Third Law of Motion