http://www.youtube.com/watch?v=TThIX7hk5bo&feature=related

Constant speed

Constant radius

Continuous acceleration of a constant magnitude directed radially toward the center

Speed = circumference/period

S=2pr/T

What is the mathematical relationship between centripetal acceleration (m/s/s) and speed(m/s) for an object undergoing UCM?◦ Consider: If the independent variable is zero,

should the dependent variable be zero?

What is the mathematical relationship between centripetal acceleration (m/s/s) and radius (m) for an object undergoing UCM?◦ Consider: If the independent variable is zero,

should the dependent variable be zero?

What is the mathematical relationship between centripetal acceleration (m/s/s) and speed(m/s) for an object undergoing UCM? (Keep the radius constant)◦ Consider: If the independent variable is zero, should the

dependent variable be zero?

What is the mathematical relationship between centripetal acceleration (m/s/s) and radius (m) for an object undergoing UCM? (Keep the speed constant)◦ Consider: If the independent variable is zero, should the

dependent variable be zero?

What happened to the centripetal acceleration when the speed doubled?

What happened to the centripetal acceleration when we kept the speed of the ladybug constant, but doubled the radius?

https://www.youtube.com/watch?v=r5L5jiKoAJw

What would happen to the net centripetal force if speed doubles but the radius stays constant?

What would happen to the net centripetal force if we keep speed constant, but double the radius?

S=2pr/T

ac = S2/r

SFc = m(S2/r)

The blades of a blender are 3.0 cm long. The blender spins at a maximum rate of 80 revolutions per second. Determine the speed and acceleration of the tips of the blades.

A 20.0 kg child rides on the edge of a 10.0 m diameter carrousel that makes one revolution every 8.00 seconds. Compute the net force acting on the child. What is the direction of that force? If the child was standing on the deck of the carrousel, what type of force would provide the net force?

In pairs, complete FreeBody Exercise #10

Copy the problem description and the completed diagram into your notes. Be sure to note any forces that balance

1. ID what you must find

2. Draw a FBD

3. ID the inward force

4. (Deal with the vertical forces if necessary)

5. Use SFc = m(S2/r)

6. Sub and solve

How fast can a 1200kg car travel around a 100m radius arc if the coefficient of _______ friction is 0.8?

What if the car’s mass doubled, but all other factors remained the same?

The Taz Twister is a ride at Great Adventure that consists of a round room with carpeted walls. Once the room is up to speed the floor is lowered, but the riders, who feel “pinned to the wall” do not drop with the floor. If the radius of the room is 7.0m, and the coefficient of ______ friction between the riders and the wall is 0.5: A) what speed must the riders have to stay “glued to

the wall”?

B) what Period must the ride have?