Angles are measured in radians;
length of an ark = radius x angle
(in radians)
Radians are SI unit for the angle used
because of trigonometry, because
rotation is measured in radians per
second, and because it has no units
Caused by change in velocity
at a constant speed
Centripetal acceleration
Given by:
Causes centripetal
force, given by:
Keeps planets in orbit of
the sun, satellites and the
moon in orbit of the earth
Do not confuse centripetal
acceleration and force!
Patterns of:
Ball on a string
Tension is centripetal force here
Conical pendulum
Gravitational fields
Act towards the mass, idiot!
Gravity is the
centripetal force here
Newtons Law of Gravitation
Definition: The gravitational force of attraction between two bodies is
proportional to the product of their masses and inversely proportional to
the distance between them. Adding in the gravitational constant, G, gives:
Note a minus sign is needed to
show it is an attractive force