an object will only accelerate if there is a net or unbalanced force acting upon it. the presence of an unbalanced force will accelerate an object – changing its speed, directions or both its speed and direction

what can cause acceleration in an object?

the resistance of any physical object to any chagne in its state of motion, including changes to its speed and direction. it is the tendency of objects to keep moving in a straight line at constant velocity. newton’s first law of motion

what is inertia

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a moving objejct will change direction if an unbalanced force acts upon it

what causes a moving object to change direction?

contact force

what force arises from direct physical contact between two objects?

1kg *m/s^2

what is the unit equivalent for a newton?

magnitude of the force

what does the length of a force vector represent?

show the relavtive magnitude & direction of all forces acting on an object in a given situation

what does a free-body diagram represent?

box

object’s representation in a free-body diagram

arrows

length of arrow proportional to magnitude of force

direction of arrow gives direction of force

each force arrow is labled & all forces acting on the object must be represented

force representation in a free-body diagram

forces that act on object, not the forces the object exerts itself on other objects

free-body diagram forces

add vectors in same direction; subtratc vectors in opposite direction

be able to determine the net force on a free body diagram

all objects upon earth experience a force of gravity that is directed “downward” towards the center of the earth

determine gravitational force on a free-body diagram

inertia

what is the term for an object to maintain its state of motino if not outside force acts upon it?

zero

a car goes forward along a level road at constant velocity. the additional force needed to bring the car into equilibrant force is what?

its a vector that is the exact same size as the resultant would be, but the equilibrant points in exactly the opposite direction

be able to calculate the equilibrant force

the upward acceleration of Earth is negligable because of its large mass

as an object falls toward Earth, what happens?

the object is accelerated

if a nonzero net force is acting on an object, then the object is what?

several forces combined

more than one force acting on an object

define net force

aimed to right

positive forces

aimed to left (canceled by positive forces)

negative forces

work together

forces in same direction

cancel each other

forces in opposite direction

work together

dont cancel each other

net force forces

inversely proportional

is acceleration directly proportional to or inversely proportional to the mass of the object

directly proportional

is acceleration directly proportional or inversely proportional to the net force of the object

force=ma

m=f/a

a=f/m

be able to calculate force, mass, and acceleration using F=ma

an object at rest will remain at rest unless acted on by an unbalanced force

an object in motion continues in motion with the same speed & in the same direction unless acted upon by an unbalanced force

“the law of inertia”

newton’s first law of motion

acceleration is produce when a force acts on a mass. the greater the mass (of the object being accelerated) the greater the amaount of force needed (to accelerate the object)

f=ma

Newton’s second law of motion

for every action there is an equal & opposite re-action.

for every force there is a reaction force that is equal in size, but opposite in direction.

whenever an object pushes another object, it gets pushed back in the opposite direction equally hard

Newton’s third law of motion

act on different objects

stimultaneous equal but opposite forces resulting from the interaction of two objects

what are action-reaction pairs?

the region of space surrounding a body

a charged particle or magnet, within which it cn exert a force on another similar body not in contact with it

what are field forces

hammer driving nail into piece of wood – hammer exerts force on nail; nail exerts force on hammer

leaf falls from tree and lands on sidewalk – leaf exerts force on sidewalk; sidewalk exerts force on leaf

ball dropped from person’s hand – earth exerts force on ball; ball exerts force on earth

give examples of action-reaction pairs

field forces

gravitational force and magnetism

mass

what is the measure of quantity of matter

weight

what is the magnitude of the gravitational force acting on an object

weight

a change in the gravitational force acting on an object

objects exert forces on each other when their fields interact

how does the theory of field forces explain how objects could exert forces on each other without touching

no units

what are the units of the coeffient of friction

force

newton of the SI unit of what physical matter

by arrows

how are force vectors represented in force diagrams

force causes an acceleration, or change in an object’s velocity.

applying the brakes decelerates the bicycle (accelerates it in negative direction) and causes a change in the bicycle’s velocity because the bicycle slows down

briefly describe how applying the brakes to stop a bicycle are an example of a force

the normal force and gravitational force vectors will cancel out in length, but the towing force vectors will be longer than the frictional force vector

construct a free-body diagram of a car being towed

scalar quantities contain only magnitude

forces have magnitude and direction

why is force not a scalar quantity

magnitude of the force

the length of the force vector is proportional to what property of a force

the object experiences an acceleration

what happens to an object in motion when it experiences a nonzero net external force

the same direction of the net force

in the equation f=ma, what is the direction of the acceleration

no, because the action force and the reaction force dont act on the same object.

the forces cancel only when they act on the same object

do action-reaction pairs result in a equilibrium?

mass will change, but weight can change depending on location

(you will weigh less on the moon as opposed to here on Earth due to the acceleration of gavity)

distinguish between mass and weight

if gravity is acting toward the center of the Earth (down) air resistance is acting upward (unless in a running scenario)

in what direction does the forece of air resistance act?

net force

what term is used to describe the vector sum of all the forces acting on an object?

for a falling object, air resistance is the friction that “stalls” free-fall movement

for a free-body diagram, a downward arrow would be drawn to represent the force due to gravity & an upward arrow drawn to represent the force of air resistance

why is air resistance considered a form of friction?

aimed in slanted direction

size of net force would not be the arithmatic sum of the sizes of the two other forces – use pythagorean theorem or trig to calculate net force

if several forces act on an object, they dont act on one line