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