Ch+4+Sec+7

Section 7
Speed increases and you want to go in a straight line and you need force to keep you on the track
 * What do you see?**

You don't fall out because your speed keeps you moving with the track
 * What do you think?**


 * Physics Talk**
 * Circular motion/acceleration
 * ac=v^2/R
 * Centripetal force
 * Fc=mv^2/R
 * Direct relationship: increase m, increase Fc
 * Direct square relationship: increase v increase FC
 * Apparent weight
 * identify direction of a
 * identify net force
 * bigger force=net force
 * a ALWAYS is towards the center
 * Net force always points to the center
 * Biggest force it toward the center


 * Checking up**
 * 1) Centripetal Force
 * 2) Yes, it takes force to keep you traveling at a constant speed
 * 3) Normal Force
 * 4) Gravity
 * 5) The larger the radius of the circle, the less force is required

1. a) b)
 * PTG**

2. a) Friction b)

6. a) No b) Yes c)

7.

10.

13. a. Heavy b. Light c. Heavy d.Heavy e. Normal

14. a. Up b. Up c. Zero d. Sideways e. Sideways


 * Physics Plus**

1)

F increases

It increases

2 It gets 4 times as big

3 Fnet gets smaller if the right side of the equation gets smaller

4. The larger the radius for the curve, the __smaller__ the force required to keep the car moving along the curve. If the curve is tight then a __greater__ force is needed.

5. The longer the curve the less force is needed to keep the car moving

Sample Problem

You don't fall out of a roller coster because of Centripetal force. Weather it is provided by weight or normal force, it keeps you on the track.
 * What do you think now?**