Presentation on theme: "Physics Chapter 13 Section 13.1 & 13.2 Why riders in a rotating carnival ride not fall out when the platform is raised? (see page 175) Spinning gives."— Presentation transcript:
Why riders in a rotating carnival ride not fall out when the platform is raised? (see page 175) Spinning gives the riders a tangential force, and the back of the seat holds them in. If you swing a tin can over your head and the string breaks, does the can fly directly outward or does it move tangent to the circle? Tangent p 180
Rotation and Revolution The axis is the point on which rotation occurs. If axis is located within a body, motion called is called rotation. (spin)
When an object turns about on its external axis, the motion is called REVOLUTION. An example of this is the Earth rotating itself and revolving around the Sun.
Rotational Speed Which is faster, a horse on the inside or outside of a merry-go-round?? Linear Speed = d/t The point on the outside moves farther in one rotation. Same rotational speed for both horses, but the one on the outside has a faster linear speed because it travels farther in a given time. We know this because:LINEAR SPEED=D/T Ex) Bugs on Record Player
ROTATIONAL SPEED= # ROTATIONS (or revolutions) in a given time Linear speed depends on distance from axis, unlike rotational speed. At center (point of rotation)- no linear speed at all – linear speed is proportional to the distance covered. 2x as far, 2x as fast (linear speed) Linear speed is proportional to rotational speed. As it turns faster (greater rotational speed) the linear speed increases.