20 terms

Portage 8 Science Ch. 2 Forces and Newton's Laws of Motion

Terms in this set (...)

inertia
The resistance of an object to change in the speed or direction of its motion; tendency of an object to keep doing what it is already doing
momentum
A measure of mass x velocity; p = m x v
Newton's First Law
Only an unbalanced force can change the motion of an object;
an object at rest remains at rest, and an object in motion will stay in constant straight motion, unless acted on by an unbalanced force.
Newton's Second Law
Force = mass X acceleration
The acceleration of an object increases with increased force and decreases with increased mass. Acceleration is in the same direction as the force.
Newton's Third Law
For every action, there is an equal and opposite reaction
centripetal force
The force that keeps objects moving in a circle; directed toward center of circle.
force
Any push or pull; measured in Newtons
net force
overall force acting on an object; forces in same directions = add them up; forces in opposite directions = subtract them
Three types of forces?
contact force, friction, gravity
F = _____ X ______
Force = mass X acceleration
fluid
anything that flows; liquids and gases are examples; water and air are more specific examples
friction
force that pulls opposite the direction of motion; caused by surfaces rubbing together; creates heat; slows motion
gravity
force pulling objects down to Earth; more massive objects have more of this force; closer objects have more of this force between them.
balanced force
net force equals zero; does not cause a change in motion
unbalanced force
net force does not equal zero; causes a change in motion
contact force
a push or pull that involves touch (for example, a foot pushing against the ground, or a hand tugging on a rope)
Conservation of Momentum
the total momentum before and after a collision stays the same
weight
the force of gravity on an object; measured in Newtons
pressure
force divided by area; P = F / A; measured in N/m2 or Pascals (Pa)
non-contact force
a force that one object can apply to another object without touching it (for example ... gravity)