Rotation – object spinning around an internal axis. Ex: a spinning top

Revolution – object spinning around an external axis. Ex: Earth moving around the Sun

Tangential Speed– the distance covered per unit of time. For circular motion distance = 2πr Expressed in m/s

Rotational Speed – number of rotations per unit of time.

Expressed in RPM (rotations per minute)

If you are standing in the exact center of a record/disc that is spinning…

- you have no tangential speed but you do have rotational speed.

Rotational speed remains constant no matter where you are on the disc

Tangential speed increases the further away from the center you get.

Centripetal Force Demonstration

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Centripetal Force – a center seeking force- causes an object to follow a circular path- Circular path Demo

m – massac – accelerationv – tangential speedr – radius

Centrifugal force - Center fleeing force

is a not a real force

What you feel is actually inertia.▪ Your body is trying to go in a straight line while the

object you are in is turning. ▪ Hence you feel as if you are being pulled outward

(away from the center).

Simulated Gravity - can be created if an object spins fast enough

…Small objects need to spin rapidly

…Large objects need to spin slower and still achieve the same gravitational effect.

***Could be used for a space station

Torque – produces circular motion Torque = perpendicular force applied

times the lever arm (distance from the fulcrum)

Fulcrum is the pivot point Torque = F┴ x d (Nm) = (N) x (m) Balanced torques ( balanced see-saw )

▪ F x d = F x d

The object is not rotatingThe Net Torque acting on the object

is zero