Seesaws Flashcards
How does a balanced seesaw move?
It rotates steadily on a fixed axis
What types of motion are there?
Translational (location) and rotational (rotation)
Give two aspects of rotation (hint: angular)
angular position: an object’s oritentation
angular velocity: the rate at which an object’s angular position is changing with time
What is the curled right hand rule?
1- curl fingers in direction of rotation
2- thumb shows official direction
What is torque?
Twisting force that disrupts rotational inertia
What is Newton’s 1st Law of Rotational Motion?
A rigid object that is not wobbling and that is free of external torques rotates at constant angular velocity
Why does a seesaw need a pivot?
The pivot prevents the seesaw from undergoing translational motion, while leaving it free to undergo rotational motion.
What is center of rotation?
The point about which all the physical quantities of rotational motion are defined
Why does a lone seesaw ride plummet to the ground?
The lone rider produces a torque on the seesaw that causes it to undergo angular acceleration
What is rotational mass?
The measure of an object’s rotational inertia
What is Newton’s 2nd Law of Rotational Motion?
Angular acceleration = net torque / rotational mass
Is it possible to produce force and not torque?
Yes, for example pulling on a door that needs to be pushed.
What is a lever arm?
Perpendicular distance to force and torque
What is the second right hand rule?
1- do a pointing motion on the lever arm
2- rotate to force
3- thumb will be pointing towards torque
How can we measure torque?
Torque = lever arm * force
Why do the rider’s weight and positions affect the seesaw’s motion?
They affect the net torque on the seesaw and therefore the seesaw’s angular acceleration
What is balanced in physics?
Experiencing zero torque due to gravity.
What is center of gravity?
The effective location of an object’s weight. On earth, it is the same as your center of mass.
Why do the rider’s distance from the pivot affect the seesaw’s responsiveness?
The farther the rider’s masses from the pivot, the greater the seesaw’s overall rotational mass, the slower its angular acceleration
How do the seesaw rider’s affect one another?
They support one another and they exchange energy as they seesaw back-and-forth.
What is Newton’s Third Law of Rotational Motion?
For every torque exerted, there is an equal oppositely directed torque exerted.
What is the formula for work?
Force * distance
