Topic 1 Movement and Force Flashcards
what is 1-dimensional motion?
the movement of a particle/subject along an x-axis
what is 2-dimensional motion?
the movement of a particle/object along an x and y-axis
define distance.
-the length the object has travelled in total.
-has magnitude only (is a scalar quantity)
-measured in meters (m)
define displacement.
-the change in an object’s position from it’s origin.
-has magnitude and direction (is a vector quantity)
-the magnitude is measured in meters (m)
-symbol is Δx
how is the magnitude of displacement represented?
the length measured along a straight line between the initial (xi) and final (xf) position of an object
define elapsed time
-the time between the initial and final time.
-symbol is Δt
initial position and final symbol
initial position= xi (i is subscript)
final position= xf (f is subscript)
initial time and final time symbol
initial time= ti (i is subscript)
final position= tf (f is subscript)
particle definition
an object that can be represented as a mass at a single point in space
the particle model of motion
a model that describes the arrangement and movement of particles in a substance
define speed
-the distance an object has covered relative to time
-is a scalar quantity
-(speed= distance/Δt)
define instantaneous speed
the speed at any particular moment
define velocity
-a vector quantity that describes how fast and in what direction an object is going.
-(velocity= change in position/change in time= Δx/Δt= xf-xi/tf-ti)
characteristics of a position vs time graph
-time is on x-axis
-position is on y-axis
-continuous curve shows the object’s position at all instances in time.
characteristics of a velocity vs time graph
-time is on x-axis
-velocity is on y-axis
-position vs time graphs can be translated into this using Δx/Δt
characteristics of acceleration vs time graph
-time is on x-axis
-acceleration is on y-axis
-
how can the velocity of an object be changed
-by changing it’s speed
-by changing it’s direction
-by changing it’s speed and direction
define acceleration
-how much an object’s velocity changes in a given amount of time.
-acceleration (a)=Δv/Δt=vf-vi/tf-ti
what is this object’s direction and velocity?
the object is moving right (vx>0) and speeding up
what is this object’s direction and velocity? (velocity vs time graph)
the object is moving right (vx>0) and slowing down
what is this object’s direction and velocity? (velocity vs time graph)
the object is moving left (vx<0) and speeding up
what is this object’s direction and velocity? (velocity vs time graph)
the object is moving left (vx<0) and slowing down
define newton’s first law of of motion/law of inertia
-with no outside forces a stationary object will never move, and a moving object will never stop.
define inertia
resistance to changes in velocity
define a force
-a force is a specific action acting on an object (push/pull).
-force doesn’t exist in isolation from the object it acts on.
-a force is a vector quantity (direction and magnitude)
what is a contact force?
-contact forces act on an object by directly coming into contact with it.
-the force lasts as long as the agent and object are in contact. (e.g. tension force, friction, spring force)
what is a long-range force/non-contact force
-act on an object without physical contact (e.g. magnetic force, weight force, electrical force)
what is weight force
-the gravitational pull on an object
-agent= entire earth pulling on an object.
-the weight vector is always vertically downward.
-symbol= w
what is spring force/elastic force
-a spring can push when compressed or pull when stretched
-symbol=F/Fsp (sp is subscript)
what is tension force
-occurs when a string/rope/wire pulls on an object.
-the tension force can only pull in the direction of the string/rope/wire
-symbol= T
what is normal force
-the force exerted by a surface (the agent) against an object pressing against the surface.
-the surface exerts a force perpendicular to itself.
what is friction
-a type of force
-like normal force, the agent is the surface, but friction is parallel to the surface.
-there are two kinds of friction, static friction and kinetic friction.
what is static friction
-a sub-type of friction and type of force
-the force that keeps an object stuck on a surface.
-the force points in the direction opposite to where the object would move if there was no friction
-symbol= fs (s as subscript)
what is kinetic friction
-a sub-type of friction and type of force
-acts as an object slides against a surface
-it opposes the motion and the force points in the direction opposite to the motion of the object.
-symbol= fk (k as subscript)
what is drag
-a type of force
-opposes motion through fluids (gases and liquids)
-drag points in the opposite direction of motion
-symbol= D
what is electrical force
-most objects are electrically neutral/have no net electrical charge
-when an object has a net electrical charge, there will be a force between the charged object and other objects
-electrical forces can be attractive or repulsive depending on the type of electrical charge.
list the types of forces
-weight force
-spring force/elastic force
-tension force
-normal force
-friction (kinetic and static)
-drag
-electrical force
mass-force relationship
-objects with more mass require more force to change velocity than lighter objects. the inertia of an object is gratified by it’s mass.
what is mass
-mass is a property of objects
-mass is a scalar quantity (magnitude) and can never be 0
-units are measured in (kg)
-an object’s mass doesn’t change according to location (mass of an object is the same on earth as it is on mars)
-mass≠weight
what is Newton’s second law of motion
-the sum of all forces on an object is proportional to the mass of the object and the force exerted on it.
-the sum of all forces=mass x acceleration (ΣF=m x a)
what is the sum of all forces
-all forces being applied on an object.
-symbol= ΣF
-AKA net force/resultant force
-m=(kg), a= (m/s2) so ΣF=(kg x m/s2)
what is the newton
-the newton is the SI unit of force.
-1N= (1kg x m/s*2)
what does it mean if ΣF= 0?
-acceleration =0
-there is no increase/decrease in velocity or change in direction
what does it mean if ΣF≠ 0?
-acceleration >0
-there is an increase/decrease in velocity or change in direction.
