Forces
includes speed and direction an object travels per unit time
velocity
a contact force that resists motion between two objects
friction
used to measure an object's motion
reference point
a group of atoms with aligned magnetic poles
magnetic domain
like charges ____
repel
a force that can act at a distance
noncontact force
a force of attraction between objects due to their masses
gravity
the acceleration of an object depends on the mass of the object and the amount of force applied
Newton's Second Law
The south pole of a magnet will ____ the south pole of another magnet.
repel
accumulation of excess electric charges on an object
static electricity
when two or more forces act on an object at the same time
net force
the amount of matter in an object
mass
an object at rest stays at rest or an object in motion stays in motion until an unbalanced force acts on it
Newton's First Law
an object that attracts or pulls on materials that contain iron
magnet
electrons have a _____________ charge
negative
the distance an object travels per unit time
speed
measure of gravitational force exerted on an object
weight
tendency of an object to resist any change in motion
inertia
Name 3 metals attracted to a magnet
iron, cobalt, and nickel
electric charges can be transferred through
friction
the rate at which velocity changes over time
acceleration
Gravity depends on __________ and ___________
mass and distance between objects.
For every action there is an equal but opposite reaction
Newton's Third Law
The strength or force between two magnets depends on the __________ between them.
space
What happens if the distance between a positively charged object and a negatively charged object increases?
The electric force decreases