Chapter 11 Physics Test Review
Chapter 11 Test Review: Rotational Equilibrium
Terms in this set (27)
What is a torque?
something produced by this turning force and tends to produce rotational acceleration
What happens when you apply a torque?
-makes an object turn or rotate
What is a lever arm?
the distance from the turning axis to the point of contact
Equation for Torque:
force * lever arm
When balanced torques act on an object..
there is no change in rotation
Does weight alone produce change in rotation?
NO. Torque does
Balance is achieved if the torque that tends to produce clockwise rotation by the bit equals..
the torque that tends to produce counterclockwise rotation by the girl
What is the Center of Mass?
where all the mass of an object can be considered to be concentrated
Where is the Center of Mass located?
at the objects average position of mass
What do we know about the motion about the center of mass?
no matter how the object is rotated, the center of mass would follow a smooth parabola
What do we know about applying spin to an object?
when you throw a ball and apply spin to it, or when you launch a plastic flying disk, such as a frisbee, a force must applied to the edge of the object
What is the center of gravity?
average position of all the particles of weight that make up an object
For everyday objects, where is the center of gravity?
the same as the center of mass
What is wobbling?
wobbling happens when the center of mass and the center of gravity are off
How do you locate the Center of Gravity?
for a uniform object, it is at the midpoint, or its geometric center
The center of gravity is also know as the..
What is the Rule for Toppling?
if the center of gravity of an object is above the area of support, the object will remain upright
EX: the leaning tower of pisa
What is balancing?
the technique of finding the over-reacting point and the under-reacting point to keep you staying upright
What is the moon's CG?
how center of gravity and torque explains the fact that only one side of the moon continually faces earth
What is the center of gravity for people?
is not located at a fixed point, but it depends on the body orientation
What is an example for the center of gravity of people?
a high jumper will have to jump high enough to get his CG above the bar
What is stability?
is to whether something will topple or if there is an adequate flat end
What is unstable equilibrium?
an object balanced so that any displacement lowers its center of mass
What is stable equilibrium?
balanced so that any displacement raises its center of mass is in stable equilibrium
What is neutral equilibrium?
an object that is balanced so that any small movement neither raises nor lowers its center of gravity
Objects in Stable Equilibrium?
when something hangs with is CG below its point of support is in stable equilibrium because the CG rises when the toy tilts
Lowering the CG of an object?
-the tendency for the CG is to take the lowest position available
-if you place a small object into a box full of stones, and have it start at the bottom of the box, the CG will be found. Then if you shake the box, the small object will come back up to the top.
-this makes the CG a lower spot in relation to the whole box