67 terms

Conceptual Physics 02: Newton's First Law

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Terms in this set (...)

Inertia
The property of things to resist changes in motion
Newton's First Law of Motion
Every object continues in a state of rest or of uniform speed in a straight line unless acted upon by an a non-zero net force
Force
In the simplest sense, a push or a pull
Net Force
The vector sum of forces that act on an object
Mechanical equilibrium
The state of an object or system of objects for which there are no changes in motion (b/c there are no net forces)
Equilibrium Rule
For any object or system of objects in equilibrium, the sum of the forces acting equals zero. ( ΣF = 0 )
Applied Force
The force exerted "onto" an object
Friction (Force)
A force, which acts in the opposite direction of the applied force, that acts to resist the relative motion of objects in contact.
Support Force
An upward force that balances the weight of an object on a surface
Weight
The downward force that an object exerts on the Earth, by nature of gravity's pull on its mass
Balanced Forces
All forces, when added, equal zero. Another way to say No Net Force
Tension Forces
The "stretching force" that acts upward on an object, and is usually seen in ropes, chains, etc.
Vector Quantity
Any quantity that is described by magnitude and direction. (i.e. Force, velocity...)
Scalar Quantity
Any quantity that is described by magnitude only. (i.e. time, mass...)
Headwind
A wind/air resistance that works as friction against the motion of an object. It serves to reduce the force, velocity, etc of the object
Tailwind
A "wind" that works as as an additional applied force that works to adds to the motion of an object. It serves to increase the force, velocity, etc of the object
Static Equilibrium
A state of motion that describes a situation where an object is at rest and all of its forces are balanced
Dynamic Equilibrium
A state of motion that describes a situation where an object is moving and all of its forces are balanced
Resultant
The sum of two or more vectors
Components
the vectors that when added together yield a resultant
weight
A measure of the force of gravity on an object's mass
newtons
A metric unit for measuring force.
Natural motion and violent motion
Aristotle divided motion into two types
Place
Aristotle believed that every object has a proper ____________ and if not in its proper ____________ it will strive to get there
Proceeds from nature of an object
Natural motion
Stone falls causing puff of smoke to arise
Examples of natural motion
quintessence
Which is known as the fifth element and says heavenly object,not on earth, move in perfect circles
Moon and Sun travel around earth
Example of quintessense
Straight up or down
Natural motion for all things on earth
Heavier
Aristotle thought what types of objects fall faster than slow
violent motion (Aristotle)
Produced by external pushes or pulls on an object
Wind imposes motion on ships, smoke blows to the side
Examples of violent motion
Galileo's discover demolished Aristotle's because he found that objects of different weights fall to the ground at the same time in the absence of what
Air resistance
Galileo believes a moving object needs no ___________ to keep it moving in the absence of friction
Force
Newton
Amount of force required to accelerate a 1 kg object at a rate of 1 meter /second
Mass
Objects with a greater ___________ have a greater inertia
Speed and direction
Inertia means that the objects ____________ and ___________ will remain constant
Downward
Balls rolling on a ____________ sloping plane will pick up speed
Upward
Balls rolling on a __________ slope will lose speed
Horizontal
A ball rolling on a ___________ plane must maintain speed forever
Friction
It a ball come to rest it is not due to "nature" but because of this force acting against it
Net forces
What causes objects to change motion, have an unbalanced force
Zero
When support and weight force are equal and object is moving at constant speed or is at rest the net force is
magnitude
In vector quantities the length of the arrow represents
Direction
In vector quantities the head of arrow represents
Force, velocity,acceleration
Examples of vector quantities
5 N to the left.
A cart is pushed to the right with a force of 15 N while being pulled to the left with a force of 20 N. The net force on the cart is
Add
When forces are the same direction
Subtract
When forces are acting in the opposite direction
Balanced forces
Equal in size or magnitude, opposite direction, do not cause change in motion
Unbalanced forces
Not equal in size or direction, cause change in motion
Zero
The vector sum of forces acting on a non-accelerating object equals
Equalibrium
When all forces are BALANCED, the object is in
The vector sum of
ΣF = 0, what does the sign mean
Hockey puck at rest on slippery ice is an example of
Static equilibrium
Hockey puck sliding at constant speed on slippery ice is an example of
Dynamic equilibrium
Copernicus
Who proposed earth was moving
Vertical
What motion was natural
Horizontal
What motion was unnatural because it require a sustained force
Copernicus
Whose calculations demonstrated that the Earth and other planets revolve around the sun, not the other way around
Galileo
Who studied Jupiter's moons
Galileo
Who is discredited with the Aristotelian theory of motion with Inertia
Three
How many laws did Newton have
An object requires a push or pull to keep it moving
Galileo's work with inclined lanes rejected a basic tenet of Aristotle which stated
The object is in mechanical equalibrium
If Fnet equals 0 then we know
Support
What force is known as the normal force
a2 + b2 = c2
Pythagorean Theorem