Chapters 10, 11 and 12 - Circular and Rotational Motion and Torque Flashcards
What the difference between rotation and revolution?
Rotation uses an internal axis and revolution is where an object goes around an external axis.
If two objects are on a merry-go-round where one is close to the middle and the other is out near the edge, which has the greater tangential speed?
The further out from the center of a rotating object, the greater the tangential speed.
If two objects are on a merry-go-round where one is close to the middle and the other is out near the edge, which has the greater rotational speed?
Every point on a rigid, rotating object has the same rotational speed.
The direction of centripetal force is always __________ .
Towards the center.
What provides the centripetal force for a car going around a curve?
The friction force between the tires and the road.
Why is centrifugal force not considered a true force?
It’s an effect of rotation. It is not part of an interaction and therefore it cannot be a true force.
The make an object turn or rotate, you must apply a ________ .
Torque.
If a 100-lb child sat 3 feet from the fulcrum of a seesaw, how far from the fulcrum would a 75-lb child sit on the other side?
100 x 3 = 75 x D so D = 4 feet
What is the center of mass?
The point located at the object’s average position of mass.
When will an object tip over?
When it’s center of mass is no longer above the area of support.
Is the center of mass of a person located in a fixed place?
No, it depends on body orientation.
The greater an object’s rotational inertia, the _________ it is to change the rotational speed of the object.
more difficult
What is rotational inertia?
resistance of an object to changes in its rotational motion (rotational “laziness)
Rotational inertia differs from regular inertia because it depends on ____________
distribution of mass.
A ring and a solid disk of similar mass are rolling down a ramp. Which one reaches the bottom first?
The solid disk because of lower rotational inertia.
