Friction
What is friction?
The force that two surfaces exert on each other when they rub against each other.
Mrs. Lathrop knocks over her coffee cup. Balanced Force or Unbalanced Force?
Unbalanced
Which has more gravity: Earth or The Moon?
Earth
Objects falling through the air experience fluid friction called what?
What is the highest height that a cat survived a fall from a building in Manhattan?
42 stories
The strength of the force of friction depends on what 2 factors?
1-How hard the surfaces are pushed together
2- The type of surfaces involved
When all forces are acting in one direction, how do you figure out the net force?
Add them together
Why does the Earth have more gravity than the Moon?
The Earth has more mass than the moon.
An object that is thrown is called a what?
Projectile
The gravitational pull on a person or object at the surface of a planet is called what?
Weight
Friction that acts on objects that are not moving is called what?
Static Friction
When two forces are equal and opposite from each other, what is the net force?
Zero
In addition to mass, what else affects the gravitational force between objects?
The distance between objects
When the only force acting on an object is gravity, the object is said to be in _______ _______. (Think of the drawing we did in class)
Free Fall
What did Galileo discover about the Earth as it relates to the sun?
The Earth travels around the sun. The sun does not revolve around the Earth.
Friction that occurs when an object moves through a fluid (i.e. water, oil, or air) is called what?
Fluid Friction
When two forces are acting opposite of each other, how do you find the net force?
Subtract the smaller force from the larger force.
9.8m/s2
If one ball is given a horizontal push at the same time another ball is dropped, they will hit the ground at the same time. True or False
True
In a vacuum, all objects fall at the same rate regardless of their ____________.
Mass
Friction that occurs when two solid surfaces slide over each other is called what?
Sliding Friction
What is the SI unit for force?
Newton (N)
What does the Law of Universal Gravitation state?
The force of gravity acts between all objects in the universe.
When the upward force of ______ ______________ on an object becomes equal to the downward force of gravity on the same object, the forces on the object are balanced.
air resistance
The greatest velocity a falling object reaches is called what?
Terminal Velocity