1. Turn in 9a

2. Circular Motion

3. Curves, Centrifugal, Centripetal Forces
Going around a curve smushes you against window
Understand this as inertia:
your body wants to
keep going straight
but the car is accelerating
towards the center of the curve
The Car accelerations
 you think you’re being accelerated

4. Centripetal, Centrifugal Forces, continued
The car is accelerated toward the center of the curve by a centripetal (center seeking) force
In your reference frame of the car, you experience a “fake”, or fictitious centrifugal “force”
Not a real force, just inertia relative to car’s acceleration
Centripetal Force
on car
velocity of car
(and the way you’d rather go)

5. Centripetal Force
What provides it?

6. Car Around a Curve - Friction
If there isn’t enough friction (icy or wet road), the car doesn’t make the curve!

8. Mythbusters!

9. Our Lab

10. Lab – How do mass, velocity and radius affect centripetal force?
Three investigations
Fc versus velocity
Mass versus velocity
Radius versus velocity
Some values are filled in already

11. Lab Notes Yesterday we discussed calculating tangential velocity.
To stop – pull down on string!
Space yourselves out.
Think ahead.
No droopage – no tiltage.
Keep strings neat and untangled.