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Physics- Newton's Laws
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Gravity
Terms in this set (43)
What did Aristotle believe was the natural state of an object?
To be at rest
What did Galileo believe to be the natural state of an object?
He believed that an object would move forever until it reaches its initial height
What did Newton believe to be an objects natural state?
To be moving at a constant speed. He was correct
What is inertia?
The tendency of an object to resist a change in motion
What is Newton's first law?
A body will move at constant velocity unless acted on by an unbalanced force.
How is inertia measured?
by mass
Units of a Newton
kg*m/s^2
Equilibrium
when the net force on an object is zero
Static equilibrium
Equilibrium of an object not in motion
Dynamic euilibrium
Equilibrium for an object in motion
Weight
A measure of the force of gravity on an object
Weight equation
W=mg
What is Newton's second law?
F=ma
What is Newton's third law?
For every action there is an equal and opposite reaction
What makes an action/reaction pair?
The forces have to be:
- equal and opposite
-acting on each other
Static friction
Friction that acts on objects that are not moving relative to each other (ex- prevents an object from sliding down a hill) Fs
kinetic friction
Friction between 2 surfaces moving against one another (box being dragged across floor). Aways opposes motion
Fk
Symbol for weight force
Fg
symbol for friction force
Ff
Symbol for Tension Force
Ft
Symbol for Applied Force
Fa
Symbol for Normal Force
Fn
Normal Force
the force perpendicular to a surface that prevents an object from falling through the surface
Tension
Rope or string force on an object
Drag
Resistance of the air (technically a fluid) against the forward movement of an airplane.
Gravitational Force equation and variables
F = Gm1m2/d^2
m1=mass 1
m2= mass 2
d=distance
F=weight
G=gravitational constant
what is the constant G?
6.67e-11 Nm^2/kg^2
Friction
A force that opposes motion between two surfaces that are in contact
Centripetal Force
the net force acting on an object toward the center of the circle
centripetal force equation (also the friction force of the object in the circle)
Fc=mv^2/r
Friction coefficient µ
ratio between friction force and normal force
µ= (two equations)
µ=Ff/Fn
µ= v^2/rg
Free fall
the motion of a falling object when the only force acting on it is gravity
circular motion
any motion in which an object is moving along a curved path
Weightlessness in free-fall
An apparent absence of weight because a person is falling freely toward the Earth, hence there is no normal force (reaction force) acting on the person due to gravity
Why can't you feel the earth spinning?
the speed is constant, we can only feel acceleration
terminal velocity
...
V average equation
Vf+Vi/2
Xtot/T
2 equations for vf
Vf=vi+at
Vf^2=Vi^2+2a(x)
Neg force=
Neg acceleration
inverse square relationship
intensity varies inversely with the distance from the source. Whatever factor by which the distance is increased, the intensity is decreased by a factor equal to the square of the distance change factor.
Why don't objects fall in circular motion?
The fall but they have sideways velocity
What does a net force of 0 mean
constant speed or motionless
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