Friction
Rubbing your hands together produces ____________ because of the force between touching objects
Heat
Smooth surfaces or rough surfaces? This one has less friction.
smooth surfaces
This describes the amount of matter an object contains
mass
This force pulls an object down toward the center of the earth
Gravity
This force slows down objects that are moving through the air
Air Resistance
Friction resists_______________
motion
This type of friction acts when objects are already moving
Sliding friction
This depends on gravity and can change when you go to a different place
weight
The force that pulls objects down also keeps planets doing this
orbiting
Critical thinking: This is why skydivers spread their arms and legs
To increase Air resistance
All types of friction try to do this
slow objects down
stop objects from moving
An example of friction working
Writing with a pen
Rubbing your hands together
Rubbing sticks together
This is how I find weight if I have the mass of an object and the gravity of a planet
Weight = mass x gravity
This force works opposite to gravity
air resistance
This scientist questioned the idea that heavier objects fall faster
Galileo Galilei
This type of friction prevents objects from starting to move
Static friction
The one that has less friction between an ice skating rink and sidewalk
ice skating rink
My mass is 100 grams. What is my weight if gravity is 10.
1000
This happens when you drop a tennis ball and a basketball at the same time (air resistance doesn't count because they are the same shape)
They hit the ground at the same time.
This was the old belief before Galileo tested falling objects
That heavier objects would fall faster
This types of friction causes balls to slow down and stop on grass
Rolling Friction
The forces that are working when a ball rolls down an incline
friction
gravity
a force to push the object and stop the object
My mass is 100g. The gravity on earth is 3.8. This is my weight on the moon.
Weight = mass x gravity
Weight = 100 x 3.8 = 380
A bowling ball and a feather have different masses, but in a vacuum they fall at the same _______
speed
Air resistance affects objects like a feather more because it has this shape
Wide and spread out