circular motion

Question 1

what is uniform circular motion?

Answer 1

Uniform circular motion is motion along a circular path in which there is no change in speed, only a change in direction.

Question 2

what is the nature of speed in uniform circular motion?

Answer 2

constant speed tangent to path

Question 3

What is the nature of the force in uniform circular motion?

Answer 3

It is a constant force that acts towards the centre

Question 4

what is needed to change direction in circular motion?

Answer 4

centripetal force is needed

Question 5

if there was a ball moving in circular motion how would it move?

Answer 5

Ball moves tangent to path, NOT outward

Question 6

what happens if centripetal force is removed?

Answer 6

When central force is removed, ball continues in straight line.

Question 7

what is continuously changing in circular motion if the speed of object is kept constant?

Answer 7

speed of the object is constant, it is continuously changing its direction

Question 8

what is the name given to acceleration in circular motion?

Answer 8

centripetal acceleration

Question 9

describe centripetal acceleration

Answer 9

acceleration that acts towards the centre of the circular path and is perpendicular to the velocity

Question 10

what is happening to velocity in circular motion?

Answer 10

velocity is changing because direction is changing therefore causing an acceleration

Question 11

what is the centripetal acceleration caused by ?

Answer 11

caused by a centripetal force that also acts perpendicular to the direction of motion - newtons second law

Question 12

equation for linear speed

Answer 12

distance/time m/s

Question 13

equation for angular speed

Answer 13

angle/time rad/s

Question 14

linear speed in terms of T (time period)

Answer 14

(2pir)/T

Question 15

angular speed in terms of T

Answer 15

2pi/T

Question 16

what is angular displacement

Answer 16

the change in angle, in radians of a body as it rotates around a circle

Question 17

angular displacement equation

Answer 17

ratio of distance travelled around the circle/ radius of circle

Question 18

how to convert degrees to radians

Answer 18

ø x π/180 = radians

Question 19

how to convert from radians to degrees

Answer 19

ø rad x 180/π = degrees

Question 20

what is angular speed?

Answer 20

the rate of change in angular disaplcement with respect to time

scalar quantity measured in radians per second

Question 21

equation
for angular speed?

Answer 21

change in angular displacement/time

Question 22

other equation for angular speed using 2pi as a complete cycle

Answer 22

v/r = 2pi f = 2pi/T

Question 23

what does the equation of angular velocity tell us?

Answer 23

• the greater the rotation angle ø in a given amount of time, the greater the angular velocity w
• an object rotating further from the centre of circle (larger radius) moved with smaller angular velocity (smaller w)

Question 24

definition of centripetal acceleration?

Answer 24

acceleration of an object towards centre of circle when an object in motion is rotating around a circle at a constant speed

Question 25

equation for centripetal acceleration

Answer 25

a = v squared/ r

Question 26

other equations for acceleration

Answer 26

a = rw squared a = vw

Question 27

why do objects have a centripetal force?

Answer 27

an object moving in a circle is not in equilibrium, it has resultant force - centripetal force

Question 28

definition of centripetal force

Answer 28

the resultant force towards centre of circle requir to keep a body in uniform circular motion, not is always directed towards the centre of the body rotation

Question 29

is centripetal force a separate force of its own?

Answer 29

no it can be any type of force depending on the situation

Question 30

what would be the centripetal force if a cat is travelling around a roundabout?

Answer 30

friction between car tyres and the road

Question 31

what would the centripetal force if a ball is attached to a rope moving in a circle

Answer 31

tension in the rope

Question 32

what is the centripetal force if the earth Is orbiting the sun

Answer 32

gravitational force

Question 33

what happens at the top of a circle?

Answer 33

at the top of a circle the weight of the object is directly contributing to the centripetal force because it is acting directly towards the centre this means that the inwards force such as for a ball being spun on a string is provided by the string - which is at minimum

Question 34

what happens at the sides of the circle?

Answer 34

the weight of the object acts perpendicular to the direction of centripetal force - meaning it makes no contribution and the force is provided externally

Question 35

what happens at the bottom of a circle?

Answer 35

the weight of the object is acting opposite to the direction of the centripetal force inwards face of string must overcome the weight and provide the required centripetal force - meaning its at maximum

Question 36

what equation can you use to find T if you are given speed and radius

Answer 36

V =( 2*pi*r )/ T

Question 37

how to find number of rotations in one minute?

Answer 37

angular speed x 60

Question 38

how do you find angle when given a time and angular speed

Answer 38

angular speed x time period given