Forces Flashcards
What is a force?
A push or a pull
What does a force cause?
It causes something to start moving, stop moving, or change direction or speed
How are forces described?
by their strength (magnitude) and by their direction, which are represented by arrows
What is the strength of force measured in?
SI Units: Newtons (N)
> named after Isaac Newton who is a British scientist, created law of motion, and the apple fell on his head
When more than one force is exerted at the same time, you can calculate the ___.
net force
What does the net force tells you
if an object will move and in what direction
Forces acting in the same direction get ____ (add/subtract/multiplied/divided) together to determine the NET FORCE.
added
If the forces are moving in the opposite direction, then you ____ to get the net force.
subtract
Forces will cancel each other out when they are ____ in magnitude and ___ in direction. Net force will equal ___.
equal, opposite, 0
When there IS a net force, the forces are considered to be ______.
unbalanced
Unbalanced forces will cause an object to _______, _____, _______.
start moving, stop moving, or change direction
When more than one force is being exerted from ___ directions but are ___ in magnitude, the result is _____.
opposite, equal, no change in motion
What is friction?
When 2 surfaces rub against each other, the force that they exert on each other is called friction
How does friction work?
Friction works opposite to motion and causes the object to slow down.
What does the strength of friction depend on?
It depends on
- how hard the surfaces are pushed together
- how rough the surfaces are
What are the four type of frictional forces?
- Static Friction
- Sliding Friction
- Fluid Friction
- Rolling Friction
What is static Friction?
It is the friction that acts on objects that are not moving.
*In order to make something move, you have to overcome static friction.
What is sliding friction?
It is the friction that occurs when two solid surfaces slide over each other.
*The rougher two surfaces are, the more friction there is Ex: shoes and the floor, hands rubbing together
What is rolling friction?
It is the friction that occurs when an object rolls a surface.
> It’s easier to overcome rolling friction because there is less surface area that comes in contact with the surface, such as a bowling ball against the floor.
What is fluid friction?
It is the friction that occurs when a solid object moves through a fluid.
> Scientists consider liquids AND gases to be fluids
(Friction in a gas is also called air resistance)
Ex: Human in a pool, bird through air
What is gravity?
It’s the force of attraction between any two objects
> It’s a pulling force
Why can we feel the force of gravity towards Earth?
We can feel it because the Earth is so massive.
What two things does gravity depend on?
it depends on:
- the MASS of the objects
- the DISTANCE between them
What is the rate of acceleration due to gravity on Earth?
It 9.8 m/s/s
*It is often rounded to 10 m/s/s
