Document Sample

Newton’s 2 nd and 3rd Law A. Newton’s 2nd Law B. Newton’s 3rd Law C. Project A. Newton’s 2nd Law The acceleration of an object is dependent upon two variables: – Fnet acting on the object – Mass of the object The acceleration of an object depends directly upon the net force acting upon the object and inversely upon the mass of the object As Fnet increases, acceleration increased As mass increases, acceleration decreases A. Newton’s 2nd Law A. Newton’s 2nd Law The net force is equal to the product of the object's mass and its acceleration. – Fnet = ma Acceleration is in the same direction as Fnet Remember: the net force is the vector sum of all the forces A. Newton’s 2nd Law What acceleration will result when a 12-N net force is applied to a 3-kg object? A 6-kg object? A net force of 16 N causes a mass to accelerate at the rate of 5 m/s2. Determine the mass. A. Newton’s 2nd Law Net Force • Fnet = ma Gravitational Force • Fgrav = mg Frictional Force • Ffrict = μ(Fnorm) A. Newton’s 2nd Law An applied force of 50 N is used to accelerate an object to the right across a frictional surface. The object encounters 10 N of friction. Use the diagram to determine the normal force, the net force, the mass, and the acceleration of the object. (Neglect air resistance.) A. Newton’s 2nd Law An applied force of 50 N is used to accelerate an object to the right across a frictional surface. The object encounters 10 N of friction. Use the diagram to determine the normal force, the net force, the mass, and the acceleration of the object. (Neglect air resistance.) Fnorm = 80 N m = 8 kg a = 5 m/s2 Fnet = 40 N, right A. Newton’s 2nd Law An applied force of 20 N is used to accelerate an object to the right across a frictional surface. The object encounters 10 N of friction. Use the diagram to determine the normal force, the net force, the coefficient of friction (µ) between the object and the surface, the mass, and the acceleration of the object. (Neglect air resistance.) A. Newton’s 2nd Law An applied force of 20 N is used to accelerate an object to the right across a frictional surface. The object encounters 10 N of friction. Use the diagram to determine the normal force, the net force, the coefficient of friction (µ) between the object and the surface, the mass, and the acceleration of the object. (Neglect air resistance.) Fnorm = 100N μ = 0.1 m = 10 kg a = 1 m/s2 right Fnet = 10N right A. Newton’s 2nd Law A 5-kg object is sliding to the right and encountering a friction force which slows it down. The coefficient of friction (µ) between the object and the surface is 0.1. Determine the force of gravity, the normal force, the force of friction, the net force, and the acceleration. (Neglect air resistance.) A. Newton’s 2nd Law A 5-kg object is sliding to the right and encountering a friction force which slows it down. The coefficient of friction (µ) between the object and the surface is 0.1. Determine the force of gravity, the normal force, the force of friction, the net force, and the acceleration. (Neglect air resistance.) Fnorm = 50N Ffrict = 5N Fgrav = 50N m = 5kg a = 1 m/s2 Fnet = 5N left B. Newton’s 3rd Law Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Action-reaction pairs never act on same object. B. Newton’s 3rd Law Two objects define a system for a Newton’s third law interaction. We are not considering (necessarily) the net force acting on an object. An object cannot exert a force on itself to cause an acceleration. Newton’s 3rd Law Action and Reaction on Different Masses Consider you and the earth Action: earth pulls on you Reaction: you pull on earth B. Newton’s 3rd Law Reaction: road pushes on tire Action: tire pushes on road B. Newton’s 3rd Law Reaction: gases push on rocket Action: rocket pushes on gases B. Newton’s 3rd Law A bug and a car collide. Which experiences the greater force? (a) bug (b) car (c) neither, they both experience the same magnitude of force B. Newton’s 3rd Law Consider hitting a baseball with a bat. If we call the force applied to the ball by the bat the action force, identify the reaction force. (a) the force applied to the bat by the hands (b) the force applied to the bat by the ball (c) the force the ball carries with it in flight (d) the centrifugal force in the swing C. Project: Balloon Rocket Racer Design a small car powered by a balloon and explain how the third law of motion describes its propulsion DUE:

DOCUMENT INFO

Shared By:

Categories:

Tags:

Stats:

views: | 0 |

posted: | 7/2/2013 |

language: | English |

pages: | 20 |

OTHER DOCS BY dffhrtcv3

How are you planning on using Docstoc?
BUSINESS
PERSONAL

By registering with docstoc.com you agree to our
privacy policy and
terms of service, and to receive content and offer notifications.

Docstoc is the premier online destination to start and grow small businesses. It hosts the best quality and widest selection of professional documents (over 20 million) and resources including expert videos, articles and productivity tools to make every small business better.

Search or Browse for any specific document or resource you need for your business. Or explore our curated resources for Starting a Business, Growing a Business or for Professional Development.

Feel free to Contact Us with any questions you might have.