* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Motion and Forces
Survey
Document related concepts
Coriolis force wikipedia , lookup
Specific impulse wikipedia , lookup
Relativistic mechanics wikipedia , lookup
Jerk (physics) wikipedia , lookup
Center of mass wikipedia , lookup
Fictitious force wikipedia , lookup
Seismometer wikipedia , lookup
Classical mechanics wikipedia , lookup
Centrifugal force wikipedia , lookup
Rigid body dynamics wikipedia , lookup
Equations of motion wikipedia , lookup
Newton's theorem of revolving orbits wikipedia , lookup
Modified Newtonian dynamics wikipedia , lookup
Centripetal force wikipedia , lookup
Transcript
Motion and Forces Ch. 8.3 Newton’s Laws of Motion Section 8.3 Objectives State Newton’s three laws of motion, and apply them to physical situations. Calculate force, mass, and acceleration with Newton’s second law. Recognize that the free-fall acceleration near Earth’s surface is independent of the mass of the falling object. Explain the difference between mass and weight. Identify paired forces on interacting objects. Newton’s First Law Newton's 1st Law States : An object at rest remains at rest and an object in motion maintains its velocity unless it experiences an unbalanced force. Newton’s 1st Law is also known as the Law of Inertia. Inertia is the tendency of an object to remain at rest or in motion with a constant velocity. Newton’s Second Law Newton’s 2nd Law States: The unbalanced force acting on an object equals the object’s mass times its acceleration. This means : force = mass x acceleration F = ma Where :F is in Newton’s (N) m is in kilograms ( kg) a is in meters per second squared (m/s2) Free fall and Weight Free fall is the motion of a body when only the force of gravity is acting on it. Weight is the force on an object due to gravity. Weight equals mass times free Free fall acceleration near fall acceleration or w = mg. Earth’s surface constant. Weight is a force and has SI Disregarding air resistance, all objects on Earth’s surface (regardless of their mass) accelerate at 9.8 m/s2. units of Newtons (N). Terminal Velocity Terminal velocity is the maximum velocity reached by a falling object that occurs when the resistance of the medium is equal to the force due to gravity. At terminal velocity, air resistance and force of gravity are equal. Sky divers reach a terminal velocity of about 320 km/h (200 mi/h). Newton’s Third Law Newton’s Third Law states: For every action force, there is an equal and opposite reaction force. Forces always occur in pairs but act on different objects. The upward push on the rocket equals the downward push on the exhaust gases. Section 8.3 Summary An object at rest remains at rest and an object in motion maintains a constant velocity unless it experiences an unbalanced force (Newton’s 1st law). The unbalanced force acting on an object equals the object’s mass times its acceleration, or F = ma (Newton’s 2nd Law). The SI unit for force is the Newton (N). Weight equals mass times free fall acceleration, or W = mg. For every action force, there is an equal and opposite reaction force (Newton’s 3rd law).