16. Circular motion Flashcards
(17 cards)
How do you convert from degrees to radians?
angle x π/180
How do you convert from radians to degrees?
radian x 180/π
What is angular velocity?
The rate of change of angle
What are the 2 equations for angular velocity?
w = 2π/T
w = 2πf
1revs^-1 =
2π rads^-1
1rads^-1 =
1/2π revs^-1
Define centripetal force
A force that keeps a body moving with a constant speed in a circular path
What direction does centripetal force always act?
Perpendicular to the velocity of the object
What direction does linear velocity act at any point on a circular path?
At a tangent to the circular path (90˚ to the radius)
What are the 2 equations from an object moving in a circle at a constant speed?
v = 2πr/T
v = wr
What is Centripetal acceleration?
The acceleration of any object travelling in a circular path at constant speed, which always acts towards the centre of the circle
What are the 2 equations for centripetal acceleration?
a = v2/r
a = w2r
What direction does centripetal acceleration always act?
Towards the centre of the circle
What are the 2 equations for Centripetal force?
F = mv2/r
F = mw2r
What are some sources of centripetal force?
- Friction for a car going round a bend
- Tension for a yo-yo spinning in a circle
- Gravitational force for a satellite circling the Earth
What is the relationship between Centripetal force and speed?
F = mv2/r
For a fixed mass and radius, Force is directly proportional to v2
The greater the speed of an object travelling in a circular path, the greater the centripetal force required to make it follow this path
Why do you feel weightless at the top of a ferris wheel?
N < mg
Fnet = mg - N
