1. Circular motion

2. Angular velocity C = 2 Π r 2 Π r v = d T Radius (m) Circumference (m)
Distance (m)
2 Π r
Speed
(m/sec)
v = d T
Period (sec)

3. Review
Whenever an object accelerates there must be a….
NET FORCE

4. Centripetal force
The force that accelerates an object inwards (towards the center of the circle )

5. Examples of Fc
A Mass is twirled in a circle at the end of a string, the Fc is provided by ________________________
When a car rounds a corner on a highway, the centripetal force is provided by
_________________________
When the moon orbits the Earth, the Fc is provided by __________________________

6. Examples of Fc Tension Friction Gravity
A Mass is twirled in a circle at the end of a string, the Fc is provided by
Tension
When a car rounds a corner on a highway, the centripetal force is provided by
Friction
When the moon orbits the Earth, the Fc is provided by
Gravity

7. Newtons 2nd law
F = MA
And we know ac = V2 r
Sooooo …..

9. Centripetal Force Fc = mv2 r Mass (kg) Linear speed (m/sec)
force (N)
Fc = mv2 r
Radius of path
(m)

11. 8.2 Calculate centripetal force
1) You are asked to find the centripetal force.
2) You are given the radius, mass, and linear speed.
3) The formula that applies is Fc = mv2 ÷ r.
4) Solve: Fc = (50 kg)(6 m/sec)2 ÷ (3 m) = 600 N
A 50-kilogram passenger on an amusement park ride stands with his back against the wall of a cylindrical room with radius of 3 m.
What is the centripetal force of the wall pressing into his back when the room spins and he is moving at 6 m/sec?