Circular & Rotational Motion - physics
centrifugal means
"center-fleeing" or "away from the center"
centripetal means
"towards the center"
what kind of speed would a ladybug have at the center of a rotating record?
(talking about the axis) - the speed in regards to both linear & rotational speed would be zero (bc the axis does not move)
**remember Newton's First Law - a body in motion wants to stay in motion in a straight line at a constant speed unless something else (gravity or friction, or centripetal force) specifically acts to change that motion**
**remember Newton's First Law - a body in motion wants to stay in motion in a straight line at a constant speed unless something else (gravity or friction, or centripetal force) specifically acts to change that motion**
if the motion is circular and executed at constant speed, this _______ force acts at _________ to the path of the moving object
-centripetal -right angles (ex. of tangential velocity)
____________ is a "real" force that counteracts the __________ & prevents an object from ______, keeping it moving instead w a uniform speed along a circular path, directed toward the center
-centripetal force -centrifugal force -flying away
difference between linear speed & rotational speed
-linear speed depends on position to the internal axis -- the farther out an object is from the center of a turntable, the greater the linear speed will be -rotational speed - all parts of a turntable have the SAME rotational speed
a point on a turntable, farther away from the center, travels a _______ in the same time as the center and therefore has a _______________
-longer distance -greater tangential speed
centripetal force is what _____ a rotating object towards __________
-pulls -the center of what it's rotating around
-the earth revolving around the sun is an example of _______ -the sun serves as the the earths ____________
-revolution -external axis
a ferris wheel ________, while the riders aboard __________ around its axis
-rotates -revolve
a turntable ________ around its axis while a lady bug sitting at its edge _________ around the same axis
-rotates -revolves
you move faster if the rate of _________ increases OR if you are farther from the ______
-rotation (bigger ω) -axis (bigger r)
greater _____ and greater ______ require greater centripetal force
-speed -mass
V = 2πr/t (__________) ω = 𝚹/t (__________) V = ωr (__________)
-tangential -angular -combined
the speed of something moving along a circular path is called ____________ because ________________
-tangential speed -the direction of motion is always tangent to the circle
1 revolution = 2πr = 360°
1 revolution = 2πr = 360°
what are the 2 types of circular motion?
1) rotation 2) revolution
formula for centripetal force
F = N (newtons) m = kg v = m/s r = m
____________ is not part of any interaction and therefore cannot be a real force
centrifugal force
a ladybug being pulled toward the base of a can that is being swung around horizontally above ones head is an example of
centrifugal force
__________ holds a car in a curved path
centripetal force
anything that moves in a circular path is acted upon by a _______________
centripetal force
compare & contrast centripetal force & centrifugal force
centripetal force is defined as the force directed toward a fixed center that causes an object to follow a circular path while centrifugal force is defined as the force that pulls outward on a rotating or revolving object -- also, centripetal force is a real force while centrifugal force is not technically a "real" force & is only felt due to inertia
units for angular velocity
degrees/sec, rad/sec, RPS, or RPM
any object moving in a circular motion undergoes an acceleration that is....
directed toward the center of the circle (centripetal acceleration)
true or false: a bug on a turntable will make more turns per minute if it is located nearer to the center of the record
false
centrifugal force describes the tendency of an object following a curved path to _____________
fly outwards (away from the center of the curve)
centrifugal force
force that pulls outward on a rotating or revolving object
if you spin a wheel, and look at how fast a point on the wheel is spinning, the answer depends on...
how far away the point is from the center
angular velocity
how fast the angle changes
units for rotational/angular speed depend on...
how many times it makes a complete circle per sec or min
which part of a record moves faster -- the outer part or the part near the axis?
in respect to -tangential speed - the outer part moves faster -rotational speed - the record rotates at the same speed on the outer part, as well as near the axis
centrifugal force is not caused by any real force but rather is felt due to _______
inertia
where does a ladybug on a rotating record have the greatest rotational speed?
it has the same rotational speed anywhere on the record
when an object moves in a circle, even at constant speed, the object still undergoes acceleration because....
its direction is changing
tangential speed is also called
linear speed
the __________ speed is greater on the outer edge of a rotating object than it is closer to the axis
linear/tangential
unit that MUST ALWAYS be used for tangential speed
m/sec
where does a ladybug sitting on a rotating record have the greatest linear speed?
on the outer edge
if given rev/sec you MUST convert to _________ when solving V=rω
radians/sec
traveling in a circular path w a smaller ________ requires greater centripetal force
radius of curvature
in rotational speed, all parts have the same _________
rate of rotation
when an object turns around an external axis, the motion is called _______
revolution
centrifugal force is an effect of _______
rotation
the earth spinning around it's own axis is an example of _______
rotation
when an object turns about an internal axis, the motion is called _______
rotation (or spin)
ALL parts of a turntable rotate at the same _____________
rotational speed (angular speed)
what serves as the centripetal force as the moon rotated around the earth?
the centripetal force is the force of gravity constantly pulling the moon toward the center of the earth (otherwise the moon would fly away in a straight line)
what serves as the centripetal force in the situation where one swings a can on a rope around horizontally over their head?
the centripetal force is your pulling on the rope so the can doesn't fly away
linear/tangential speed is...
the distance traveled per unit of time (V=d/t)
centripetal force
the force directed toward a fixed center that causes an object to follow a circular path
rotational speed
the number of rotations per unit of time
the centripetal force of an object depends on....
the object's tangential speed, its mass, and the radius of its circular path
axis
the straight line around which rotation takes place
a tin can whirled on the end of a string moves in a circle because...
the string continually pulls inward on the can
a centripetal force is often called fictitious because....
there is no mass pulling outward
units for rotational/angular speed
RPS, RPM, degrees/sec, or rad/s
formula for tangential speed
V=2πr/t
formula connecting linear speed (tangential speed) & angular speed (rotational speed)
V=rω v = tangential speed r = radial distance ω = rotational speed (rads/sec)
centrifugal force is caused by...
a reaction due to something rotating -- note caused by mass pushing it outward
internal axis
an axis located within the body of the object
as an object rotates, the change in the angle is called the object's ____________
angular displacement
rotational speed is also called
angular speed/velocity
although points at different distances from the center of a rotating wheel have different velocities, they all have the same ____________
angular velocity (they all go around the same number of revolutions per minute and the same number of radians per second)
centripetal force points toward the _____ of the rotating system
center
true or false: a rotation takes place about an internal axis and a revolution takes place about an external axis
true
true or false: any force that causes an object to move in a circular path is called a centripetal force
true
true or false: the outside rim of a rotating turntable has a greater linear speed than parts closer to the axis
true
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
tangential speed
varies w position -- depends on position to the internal axis