force
a push or pull that acts on an object
newton
the force that causes a 1-kilogram mass to accelerate at a rate of 1 meter per second each second
net force
the overall force acting on an object after all forces are combined
friction
a force that opposes the motion of objects that touch as they move past each other
static friction
the friction force that acts on objects that are not moving
rolling friction
the friction force that acts on rolling objects
fluid friction
the friction force that opposes the motion of an object through a fluid
gravity
the force that acts between any two masses
terminal velocity
the constant velocity of a falling object when the force of air resistance equals the force of gravity
projectile motion
the motion of a falling object after it is given an initial forward velocity
inertia
the tendency of an object to resist a change in motion
mass
the amount of matter an object contains
weight
the measure of the force of gravity on an object
momentum
the product of an object's mass and velocity
law of conservation of momentum
the total momentum of a closed system does not change
electromagnetic force
a force associated with charged particles, which has two aspects, electric force and magnetic force
strong nuclear force
a powerful force of attraction that acts only on the neutrons and protons in the nucleus, holding them together
weak nuclear force
a powerful attractive force that acts over a short range
gravitational force
an attractive force that acts between any two masses
centripetal force
a center-directed force that continuously changes the direction of an object to make it move in a circle