Motion & Forces Flashcards
Motion
When the distance between and object and a reference point changes
Reference point
The stationary object used to see whether another object is moving in relation to it
Displacement
The different between an object’s initial and final position
Speed
The distance an object travels in one unit of time
Speed formula
Speed = distance/time
(units = m/s or km/hr)
Constant speed
Stays the same the entire time
(Ex. horse, car in cruise control, boat)
Instantaneous speed
At a specific moment in time
(Ex. radar gun, speedometer in car)
Average speed
Overall speed on a trip (total distance/total time)
Velocity
Speed in a given direction; has the same formula as speed
(Ex. weather forecast, airplane pilot)
Resultant velocity
When you combine multiple velocity is to get a total velocity
(Ex. plane velocity (100 km/hr) PLUS opposing wind velocity (25 km/hr) = 75 km/hr)
Acceleration
Rate at which velocity changes
- increase/decrease speed
- change direction (Ferris wheel, orbit)
Acceleration Formula
(Final velocity - initial velocity)/time
Units = m/s sq. or km/s sq.
Distance traveled
The total length of a path.
Slope
The steepness of the line on a graph 
Basic SI unit of length
Meter
Horizontal line
Object has a constant speed
Distance - time graph
Time is plotted on the x-axis and speed or velocity is plotted on the Y axis. The deeper the graph, the faster the motion. A downward sloping line means the object is returning to the start.
Weight
The measure of gravitational force on an object that changes with each planet.
Unit = Newtons (N)
Force
A change in motion or acceleration of an object (a push or pull)
Force formula
Force = mass x acceleration
Contact force
Must touch
Noncontact force
Does not touch, for example, gravity and magnetism.
Unbalanced force 
Object will change its state of motion 
Balanced force
Object will not change its state of motion
Centripetal force
A force on something with a circular path, and directs the object toward the center around where it is moving. For example, the moon in orbit, or a roller coaster loop.
Gravity
The force of attraction between objects due to mass
Law of universal gravitation
Depends on mass and distance if force increases, mass increases, and if force increases distance decreases.
Friction
A force that resists motion between two surfaces, and can be helpful or harmful.
Kinetic friction
Moving
Static friction
Not moving
Sliding friction
Solid surfaces slide over each other
Rolling friction
An object rolls over a surface with a circular motion
Fluid friction
An object moves through a fluid (gas or liquid)
Reducing friction
Lubricants, adding wheels, or making surfaces smoother
Increasing friction
Make surfaces rougher, or increase force between the services by adding weight/pressure
Newtons law of inertia
Objects in motion, book heat, moving at the same speed, and in the same direction, unless force changes their motion. Objects at rest will stay at rest unless a force makes them move.
Newtons law of acceleration
An unbalanced force causes a change in speed which causes acceleration
Newtons law of action and reaction
For every action, there is an equal and opposite reaction when two things collide, they press against each other with equal force in opposite directions when two objects with unequal Mascalaito, the objects will accelerate at different rates
Freefall
The state that exists, when only the force of gravity is acting on an object
Terminal velocity
A following object reaches this, when forces of gravity and air assistance are balanced
Air resistance
The kind of friction that slows a falling object
