* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Circular Motion
Survey
Document related concepts
Lorentz force wikipedia , lookup
Pioneer anomaly wikipedia , lookup
Mechanics of planar particle motion wikipedia , lookup
Torque wrench wikipedia , lookup
Modified Newtonian dynamics wikipedia , lookup
Friction-plate electromagnetic couplings wikipedia , lookup
Artificial gravity wikipedia , lookup
Coriolis force wikipedia , lookup
Centrifugal force wikipedia , lookup
Fictitious force wikipedia , lookup
Transcript
Forces and Motion in Two Dimensions Circular Motion Objectives Explain the acceleration of an object moving in a circle at constant speed Describe how centripetal acceleration depends upon the object’s speed and the radius of the circle Recognize the direction of the force that causes centripetal acceleration Explain how the rate of circular motion is changed by exerting torque on it Describing Circular Motion The position of the object relative to the center of the circle is the position vector R. During its path, the length of the vector doesn’t change, but the direction does. v1 r1 r2 v2 Describing Circular Motion To find velocity, first find the displacement vector (∆r) or (r2-r1) over a time interval (∆t.) ¯v = Δr / Δt A moving object’s average velocity is ∆d / ∆t. But for an object in circular motion, the average velocity is ∆r / ∆t. Describing Circular Motion The velocity is at right angles to the position vector and tangent to the circular path. ∆V is found by subtracting the vectors V2 and V1. Centripetal Acceleration Centripetal acceleration is the acceleration of an object in uniform circular motion and is always pointed toward the center of the circle. Centripetal Acceleration Acceleration is ∆V/ ∆t and is directed toward the center. ac = v2/r Centripetal Acceleration Period (t) = the time needed for an object to make a complete revolution, the circumference of the circle, 2πr. The object’s speed is represented by: V = 2πr/t So, substitute 2πr/t for V and the centripetal acceleration is: Ac = (2πr/t)2 / r or 4π2r / t2 Torque In relation to uniform circular motion, you have considered objects such as a person on a merry-go-round These can be considered point masses Now, consider rigid rotating objects A mass that rotates around its own axis Ex: doors Torque To open a door, you push at a distance from the hinges (axis of rotation) and in a direction perpendicular to the door The product of the force applied to an object, the distance from the rotation point, and the direction of the force applied is called torque Unit is for torque is Newton meters (Nm) Torque Solve for torque using the following equation: T = r FsinΘ T = torque r= radius F= force applied Θ= direction