Conceptual Physics Chapters 9 & 10 (Circular Motion & Center of Gravity and Center of Mass) :)
What is another name for rotational speed?
Angular speed
Is RPM a unit of linear speed, or is it a unit of spin? (linear/tangential speed or rotational/revolutional speed)
rotational/revolutional speed
What does RPM stand for?
rotations/revolutions per minute
What will people living on the outer edge experience?
1.0 g of gravity, which is the same value found at Earth's surface
What is the name of the concept in chapter 9 that is sometimes referred to as an apparent reality force?
centrifugal
What term is described as "center-fleeing"?
centrifugal force
Describe the force that acts on your clothes during the spin cycle of your automatic clothes washer?
centripetal
What is the name given to any force that is directed at the right angle to the path of a moving object and tends to produce circular motion?
centripetal force
What term is described as "center-seeking"?
centripetal force
What would happen to your weight if the Earth should happen to speed up its rate of rotation?
decrease
What would happen to a person's weight should the same space habitat slow down its rotation?
decreases
true or false: A bug on a turning phonograph record will make more turns per minute if it is located toward the center of the record.
false
true or false: From within a rotating frame reference (i.e. space habitat), there is an outwardly-directed centrifugal force.
false
true or false: The only reason riders on a rotating platform on a carnival ride don't fall off because they are strapped in.
false
true or false: the center of mass of an object is always located at the object's geometric center.
false
The speedometer in a car is driven by a cable connected to a shaft that turns the car's wheels. What will the speedometer reading be when the car's wheels are replaced with smaller ones.
it will read the same.
What happens to the CG of a tapered cup filled with water when a Ping-Pongball is plunged downward into the water?
it will rise
What happens to an object when its CG does not extend beyond its support base - will it topple or stay up right?
stay up right
If you loose your grip on a rapidly spinning merry-go-round and fall off, in which direction will you fall off?
tangent
When a string breaks, a whirling tin can will then move in a straight line ________ to its circular path, providing that no other force is acting on it.
tangent
What is linear speed called when something moves in a circle?
tangential
What is another name for linear speed?
tangential speed
Is a person's CG a fixed point, or can we vary our CG's position by changing our body's configuration?
yes
Is there a difference between a man and a women CG?
yes
Will it be possible for people in the future to live inside a rotating space habitat?
yes
If you touch your toes while standing flat against a wall, why will you topple over?
your CG passes your support base
What is toppling?
when an object extends beyond its support base
Where is the first song played on a CD?
inside
What is the centripetal force needed to make a 1000.0 kg car traveling at 5.00 m/s around a turn 30.0 m in radius?
((1000.0kg x 2m^2/s^2) / 30.0 m) = 833 kg x m/s^2
What are the steps involved for finding the CG of a map of the Continental United States?
(1.) Suspend the map against a wall allowing it to hang freely; 2.) Attach a plum line to the map; 3.) Trace the line made by the plum line;)
A merry-go-round rotates around 100.0 times in 4.5 minutes. What is the merry-go-round's rotational speed?
(100.0/4.5=) 22 RPM
For a car to go around a curve, there must be sufficient ______ to provide the required centripetal force. If the force of _______ is not great enough, skidding occurs.
(a) friction (b) friction
A ladybug inside a tine can is being whirled around horizontally. 1)What exerts a force on the ladybug and 2)in what direction is this force and 3)what is the name of this force?
1) the can 2) outward 3) centripetal
What can a spider monkey vary with its long heavy tail?
CG (which aids its balance)
How do you find the CG for a metric ruler?
Determine where the geometric center of ruler (for a meter stick this is at 50.00 cm) and then balance it on your finger.
Where would you currently weigh more: at the North Pole or at the equator?
North Pole (you weigh less at Earth's equator due to Earth's greater tangential speed)
What is the difference between CG and CM?
Objects have no CG in space, but do have CM (The CG is the average point of weight, and the center of mass is the average point of mass; the pull of gravity is the same at Earth's surface, so we can interchange CG with CM. However, one can not have a CG in space, but you will have a CM in space.)
How are linear speed and the distance from the center of a rotating platform related?
Proportional
How are linear speed and rotational speed related to each other?
Proportional (As the linear speed increases, so does the rotational speed.)
What is the difference between rotation and revolution?
Rotation: sling around internal axis; Revolution: spin around external axis
You currently live in the Northern Hemisphere. In what direction of travel would you take if you wanted to decrease your weight?
south
A spoon is slid spinning across a table. What path would it CG take?
a straight path (because it's on a flat, 2D surface)
What does the term tangent mean?
a straight path that touches a curved path
If the Earth should happen to rotate slower about its axis, what would happen to you weight?
increase
As the speed of the space habitat increases, what happens to the weight of the people inside?
increases
Where on a record would you find the last song?
inside
Which has a smaller linear sped, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
inside
A spacewomen hovers in space beside a rotating space station in outer space. Both she and the center of mass station are at relative rest. If the space station is in orbit, then she...
is also in Earth's orbit.
A car travels in a circle at a constant speed. The net force on the car...
is directed toward the center of the curve
Does centripetal force do work on a rotating object?
no
Is the CM for an object always located at the object's geometric center?
no
can an object have more than one CG?
no
You currently live in the Northern Hemisphere. In what direction should you travel to increase your weight?
north
Where do you put the needle on a record to play the first song
outside
Which has the greater linear speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
outside
Where is the CG for our solar system located?
outside the sun
What could you use to determine whether or not the CG has extend beyond an object's support base?
plumb line
A picture hangs on a wall by a wire that is passed over a supporting nail. The picture is in stable equilibrium. After any slight push, will the picture be raised, lowered, or will it remain in its same location.
raised
If a shovel were thrown in the air, what path would its CG take?
smooth parabolic path
In what direction of travel would you take if you lived in the Southern Hemisphere?
south
Where is the CG for a donut?
the hole
When a railroad train rounds a banked track, the centripetal force needed comes not from friction, but from the...
the horizontal component of the normal force
Where is the CG of a shovel located?
the massive end
The centripetal force extended on a motorcyclist, while riding on the inner vertical surface of a circular track is...
the normal force (support force)
What do objects thrown into the air rotate around?
their CG (objects do not always rotate around the geometric center, but do rotate around their CG)
Where is the CM of a human body located she a person is standing upright?
their chest/belly
true or false: When you whirl a can on the end of a string, the centripetal force on the can is actually the pull of the string on the can.
true
true or false: a straight line about at which rotation takes place is called the axis.
true
true or false: an unaided object will topple over if its center of gravity extends beyond its support force.
true
true or false: when an object moves in a circle, there is no force pushing the object outward. The true force responsible is center-seeking.
true
