Unit 4 Flashcards
(71 cards)
centrifugal force
- The apparent outward force on a rotating or revolving body.
- It is an effect of rotation.
- Is fictitious because it is not part of an interaction, and therefore not a true force.
- Is due to the tendency of a moving body to move in a straight-line path.
What moves faster on a disk?
Inside and outside have the same rpm, but the outside part moves faster than the inside.
Can the terms linear speed and rotational speed be used interchangeably?
No. [see sec 10.2]
A satellite is…
constantly changing direction as it travels around the Earth, and so it is constantly accelerating. B/c it is accelerating, it is experiencing a net force, gravity.
axis
straight line around which rotation takes place
Two types of circular motion
Rotation and revolution
Rotation
motion about an axis located within the body of the object
internal axis
an axis located within the body of the object
Revolution
the motion about an axis located outside the body of an object
Linear speed
distance traveled per unit of time
Tangential speed
The speed of an object moving in a circular path. Called this because the direction of motion is always tangent to the circle.
Rotational speed.
aka angular speed. Number of rotations per minute (rpm).
A point farther away from the center travels…
…a longer path in the same time, and therefore, has a greater tangential speed.
tangential speed proportion
tangential speed ~ radial distance * rotational speed or v ~ r*w
What does tangential speed depends on?
Rotational speed and the distance from the axis of rotation
Why does a moving freight train stay on the tracks?
Because their rims are slightly tapered.
An object moving in a circle still undergoes…
…an acceleration, even at a constant speed, because its direction is changing, which is due to net force.
Centripetal acceleration
What any object moving in a circle undergoes an acceleration that is directed to the center of the circle.
Centripetal
means “toward the center.”
What would happen if a centripetal force ceased to act on an object moving in a curved path?
the object would move in a straight line.
the centripetal force that holds a car in a curved path while rounding a corner comes from.
comes from the friction between the tires and the road.
When you are riding in a car and it goes around a sharp left-hand corner, why are you pressed against the door of the car?
There is no centripetal force acting to hold you in place.
What causes the centrifugal-force effect?
Inertia
In a rotating reference frame, what forces act on objects in the rotating system?
Both centripetal and centrifugal forces