Chapter 16: Circular Motion

Question 1

How are angles measured in this section?

Answer 1

Radians

Question 2

arc length expression

Answer 2

rθ

Question 3

Degrees to Radians

Answer 3

radians = (π x degrees) / 180

Question 4

Angular Velocity

Answer 4

angle at object rotates through per second

Question 5

Angular velocity equation

Answer 5

ω = θ/t

Question 6

How can angular velocity be expressed?

Answer 6

magnitude of angular velocity can be written in terms of the magnitude of linear velocity

Question 7

equation linking linear and angular velocity

Answer 7

v = ωr

Question 8

Frequency

Answer 8

number of complete revolutions per second

Question 9

Period

Answer 9

time taken for a complete revolution

Question 10

angular velocity for a complete circle

Answer 10

ω = 2π/T

Question 11

angular velocity in terms of frequency

Answer 11

ω = 2πf

Question 12

Centripetal Acceleration

Answer 12

car accelerating but not going any faster, as constantly changing direction

Question 13

centripetal acceleration in terms of linear velocity

Answer 13

a = v^2/r

Question 14

Centripetal acceleration in terms of angular velocity

Answer 14

a = ω^2 r

Question 15

Centripetal force

Answer 15

circular motion caused by a constant net force perpendicular to velocity, no work is done on the object, KE is constant

Question 16

centripetal force in terms of linear velocity

Answer 16

F = mv^2/r

Question 17

centripetal force in terms of angular velocity

Answer 17

F = mω^2 r

Question 18

How can you investigate circular motion

Answer 18

using a rubber bung, some washers, some string and a clear plastic tube

Question 19

Method to investigate circular motion

Answer 19

Measure the mass of the bung and mass of the washers
Thread the string through the plastic tube
Make a reference mark on the string, measure from mark to centre of the bung
mark up with the top of the tube, spin the bung in a horizontal circle
Measure time taken to make a complete circle
Use equations to find angular velocity and centripetal force
Repeat for different r, radius of bungie path

Question 20

True or False: The centripetal force and velocity of an object moving in a circle are always in the same direction

Answer 20

False
Velocity is always at a tangent to the circle, force along the radius, they are perpendicular

Question 21

True or False: An object moving in a circle at a constant speed is not accelerating

Answer 21

False
Direction is always changing hence velocity is always changing, hence accelerating