# 7th Grade Science Force and Motion

## 52 terms · Key vocab, Newton's 3 Laws of Physics, and more!

### Force

a push or pull; all ****** have both size and direction

### Magnetic Force

the force exerted between magnetic poles, producing magnetization

### Elastic Force

the force that is released when something is being pulled or compressed

### Electrical Force

force exerted due to motion of electrons; electrons flow from higher potential to lower and preform work

### Bouyant Force

the upward force the fluids exert on all matter; bouyant force opposes gravitational force

### Friction

a force that opposes motion between tow surfaces that are touching

### gravity

a force of attraction between objects that is due to their masses

### speed

the rate at which an object moves; ***** depends on the distance traveled and the time taken to travel that distance

### velocity

the speed of an object in a particular direction
Speed+Direction=V*******

### friction

a force that opposes motion between two surfaces that are touching

### newton

(N) the SI unit of force
Ex:11N

### weight

a measure of the gravitional force exerted on an object, usually by the Earth

### agent

what causes an object to change motion

### reciever

what recieves the impact of force

### contact force

a force in which the agent does not directly have come in contact with the receiver

### non-contact force

a force in which the agent doesn't have to come in contact with the receiver

### balenced forces

when two equal but opposite forces act on an object, the object stays stationary

### unbalenced forces

when two unequal and opposite forces act on an obect , the object moves in the direction of the greater force

### All vector diagrams must have:

Diagram
Arrow
Force
Direction of Force
Agent
Reciever
Result of force

### net force

the force that results from combining all the forces exerted on an object

### law of universal gravitation

the law that states that all objects in the universe attract each other through gravitational force

### speed

is a ratio of the distance traveled to the time it took to travel that distance
S****=distance/time Ex:20km/h

Newtons!

### mass

the amount of matter in an object; stays the same no matter where in the universe you measure it (measured in a double pan balence).

### momentum

property of a moving object that depends on the object's mass and velocity; NOT A FORCE
M*******=Mass times velocity/speed

### inertia

an object at rest or in motion will stay at rest or in motion unless acted upon by another force

### Newton's 1st Law

Every object in a state of uniform tends to remain in a state of motion unless an eternal force is applied
To Sum it All Up: INERTIA

### Newton's 2nd Law

The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector.

### Newton's 3rd Law

For every action there is an equal and opposite reaction.
To Sum it Up: For every agent there is a reciever.

### lubricant

a substance capable of reducing friction by making surfaces smooth or slippery
Ex: water, oil, grease, slime

### contact forces

forces that push or pull using direct contact with one another. Ex: you pushing your chair in after you get up (push of hand)

### non-contact forces

forces that push or pull without needing direct contact. Ex: when you rub a balloon on your hair then hold it by your head and your hair sticks up (static force)

### double pan balance

A double-pan balance is a scale which has 2 pans that are balanced against each other. The scale functions like a see-saw, with each of the 2 pans attached to a beam over a centered pivot point.

### acceleration

an increase in speed

### scale

pattern, make, regulate, set, measure, or estimate according to some rate or standard

### size and direction

- what all forces have
-two things you must take into account to calculate net force

### average speed

a rate of motion determined by dividing the total distance traveled by the total travel time

### Law of Conservation of Momentum

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

### the formula of force

MASS x ACCELERATION = FORCE!

### action/ reaction forces

forces always act in pairs, action forces being the "start"/cause/agent and the reaction forces being the "end/effect/reciever.

### variables that affect friction

-surface area
-type of surface
-wheels or no wheels
-mass/weight of object
-if there are any fluids on the upcoming surface

### variables that do NOT affect friction

-color of object
-length of object
-amount of newtons

### varibles that affect accleration

-speed
-velocity
-amount of mass the object has
-force that moved the object
-surface of the object

### distance

the property created by the space between two objects or points

### density

the amount of matter in a given space; mass per unit volume

### rolling friction

requires little force; MUST HAVE WHEELS!
Ex: bikes,cars,skates,planes,etc

### sliding friction

very hard to move; requires lot of force; THE HARDEST PART OF PUSHING!
Ex: sledding, brakes, writing with a piece of chalk

### fluid friction

opposes the motion of objects traveling through fluids; MUST HAVE FLUIDS!
Ex: swimming,slipping on water, wiping spilt milk

### static friction

the friction you feel when starting to push something; THE FRICTION THAT KEEPS OBJECTS IN PLACE

### lubrication

the condition of having been made smooth or slippery by the appliacation of a lubricant

### centripical acceleration

the effects of inertia and rotation; the circular motion causes constant acceleration

### centrifugal force

FICTITIOUS FORCE; NOT A REAL FORCE
An apparent force that acts outward on a body moving around a center, arising from body's inertia