Forces Flashcards
force
a push or pull that is a vector quantity
a force is described by its __________ and by the __________ in which it acts
magnitude; direction
What is an arrow used for to represent a part of a force?
its direction and strength
Newton
the SI unit for magnitude or strength of a force
When an object is subject to two or more forces at once, what is the resulting combination?
it effects all the forces
net force
the combination of all forces acting on an object that determines whether an object moves and in what direction it will move
when two or more forces act in the same direction, the net force is found by adding what?
the strength of the individual forces
adding a force acting in one direction to a force in the opposite direction is the same as what?
adding a positive to a negtave
the opposing force are equal in strength which means…
there’s no net force
unbalanced forces
the cause of the velocity of an object to change (speed up, slow down, or change direction)
unbalanced forces acting on an object result in a net force and causes a change in the objects…
velocity
balanced forces
when equal forces act on one object in opposite direction
balanced forces acting on an object do not change the objects…
velocity
friction
a force that acts in a direction opposite to the motion and is also the force that two surfaces exert on each other when they rub against each other
with friction or another ubnbalanced force, what will a moving object not do?
it will not stop until it strikes another object
the strength of the force of friction depends on what types of surfaces are involved?
how hard they’re able to be pushed together
friction increases if…
surfaces push hard against each other
Why do smooth surface produce less friction than rough surfaces?
when the irregularities of one surface comes into contact with those of another surface, friction occurs
static friction
the friction that acts on objects that are not moving
you must use extra force to start the motion of…
stationary objects
sliding friction
a balanced force when two solid surfaces slide over each other
when an object is pulled at a constant velocity across a level surface, the puling force equals…
the sliding friction
rolling friction
when an object rolls across a surface
fluid friction
when a solid object moves through a fluid (water, oil, air, and materials that flow easily)
gravity
a force that pulls objects toward each othern
universal law of gravitation
a law made by Newton that states that the force of gravity acts between all objects in the universe without exception attract each other
you don’t notice the attraction among objects because…
these forces are small compared to the forces on Earth’s attraction
the force of gravity between objects increases and decreases by what?
increases-greater mass
decreases-greater distance
mass
the measure of the amount of matter in an object
what is the SI unit for kilograms?
mass
the gravitational force of mass depends on the distance between…
objects (the lesser the gravitational force, the farther apart they are)
weight
the gravitational force exerted on a person or object at the surface of a planet
what is the equation for weight?
weight = mass*acceleration due to gravity
unlike mass, weight varies with the strength of what?
the gravitational force
free fall
when the only force acting on a n object is gravity that is accelearting
in free fall, the force of gravity alone causes an object to what I’d the downward directin?
accelerate
air resistance
a type of fluid friction that acts on objects falling through air that is an upward force exerted on falling objects
projectile
an object that is thrown
compression
an elastic force that squeezes or pushes matter togethere
tension
an elastic force that stretches or pulls mattertons
Newtons first law of motion (the law of inertia)
states that an object will remain at rest or moving at a constant velocity unless it is acted by an unbalanced force
inertia
the tendency of an object to resist a change in motion
newtons second law of motion
states that acceleration depends on the net force acting of the object and on the objects amss
what two equation mean the same when it comes to acceleration or net force?
acceleration=net force/mass
net force= mass*acceleration
newtons third law of motion
states that if one object exerts a force on another object then the second object exerts a force of equal strength in the opposite direction; for every action, there is an equal opposite reaction
what is the quantity of motion
a Newton that is part of all moving objects
momentum
a characteristic of a moving object that depends on both the mass and velocity of the ovjectou
what is the equation for momentum
momentum = mass*velocity
the law of conservation of momentum
int eh absence of outside forces the total momentum of objects that interact does not change
the total momentum of any group of objects remain the same or…
is conserved unless outside force act on the objects
thrust
an upward force that is greater than the downward pull of gravity
satellite
any object that orbits another object in space
an object traveling in a circle is constantly changing direction so it is…
acceleratingi
f an object is accelerating it means…
an unbalanced force must be acting on it
tripetal force
any force that causes an object to omv ein a circular path
