1. WARM UP: Please grab your sheet from yesterday.
Finish the WEIGHT calculations from the FRONT by multiplying your mass in NEWTONS by the GRAVITATIONAL FORCE on each planet
Complete the backside of the sheet by diving the weight on each planet by Nicki Minaj’s mass (50 kg). CALCULATED FROM THE INFO ON PLANET EARTH…

2. Announcements

3. Notebook Quiz What is the definition of POSITION?
What is the unit of FORCE?
What is the formula to calculate speed?
What do you plot along the Y-axis on a Distance-Time graph?

4. FRICTION

5. The force that slows the ball to a stop is FRICTION.
What will happen when the ball is released?
When the ball reaches the bottom of the slope, will it keep moving forever?
The force that slows the ball to a stop is FRICTION.
Since the ball stops, there must be a force acting to slow the ball down.

6. What is Friction?
Friction is a force that two surfaces exert on each other when they rub against each other.
The direction of the friction force is always OPPOSITE to the direction of the motion.
Direction of Motion
Friction Force

7. Types of Friction
Fluid friction occurs when a solid object moves through a liquid or gas.
Air resistance is a type of fluid friction.
Direction of Motion
Friction Force

8. Sliding Friction Force
Types of Friction
Sliding friction occurs when two solids slide over each other.
Sliding friction makes car brakes work and stops athletes from slipping.
Direction of Slide
Sliding Friction Force

9. Types of Friction
Rolling friction occurs when an object rolls across a surface.
Rolling friction is easier to overcome than sliding friction for the same materials.
Direction of Motion
Friction Force

10. Direction of Intended Movement
Types of Friction
Static Friction opposes the motion of an object that is at rest
To make the object move, you have to exert a force larger than the force of static friction.
Direction of Intended Movement
Static Friction Force

11. Which type of friction is slowing down the object in each situation?
You are slipping down a waterslide at Treasure Island in Orlando!
You use a lot of force to slide a desk across the floor.
You’re riding a skateboard down the street and it slowly rolls to a stop.
You try to push the couch, but can’t seem to move it.
FLUID FRICTION
SLIDING FRICTION
ROLLING FRICTION
STATIC FRICTION
Friction Force

12. LAB PRACTICE!
MU OF THE SHOE!!!

13. EXIT TICKET
What happens when you wear socks and walk on a wood or tile floor? Why do you think this happens?
What causes a baseball or football to slow down in the air?
How many forces are acting on you when you sleep? How many forces are acting on you when you sit in class?