science chapter 2.1.2 Flashcards
a push or a pull on an object
force
a push or a pull on an object by another that is touching it
contact force
a force that one can apply to another object without touching it
noncontact force
Name 3 types of noncontact forces
gravity, magnetic forces, and electric forces
When using arrows to show forces, the longer the arrow, the…
stronger the force
The SI unit for force
Newton (N)
an attractive force that exists between all objects that have mass
gravity
the amount of matter in an object
mass
The unit used for measuring mass
kilograms (kg)
Sir Isaac Newton discovered…
the law of universal gravitation
states that all objects are attracted to each other by a gravitational force
the law of universal gravitation
the strength of gravitational forces depends on…
the mass of each object and the distance between them
when the mass between one or both of two objects increases, the…
gravitational force between them also increases
The attraction between two objects decreases as…
the distance between the objects increases
the gravitational force exerted on an object
weight
weight is also measured in…
Newtons (N)
An objects weight is ___________ to its mass
proportional
When near earths surface, the weight of an object in newtons is about __________ its mass in kilograms
10 times
Weight in space is _____ of what it was on earth
90%
a force that resists the motion of two surfaces that are touching
friction
prevents surfaces from sliding past each other
static friction
opposes the motion of surfaces sliding past each other
sliding friction
between a surface and a fluid-any material, like water or oil, that flows
fluid friction
Friction is caused by….
bumps and ridges on surfaces or weak electric charges in objects
decreases friction
lubricants
less friction =
more sliding
The combination of all forces acting on an object is the
net force
forces acting on an object that combine and form a net force of zero
balanced forces
forces acting on an object that combine and form a net force that is not zero
unbalanced forces
according to Newton’s __________________, if the net force on an object is zero, the motion of the object does not change
Newton’s first law of motion
the constant velocity reached when air resistance equals the force of gravity acting on a falling object
Terminal Velocity
The tendency of an object to resist a change in its motion
inertia
if there was no friction, object would…
continue moving at the constant force they are at because of inertia
objects stop moving because
friction or another force acts on them
