Matter in Motion
When an object changes position over
time when compared with a reference
point, the object is in
motion.
The rate at which an object moves is its
speed.
The speed of an object in a particular
direction is the object’s
velocity.
____ is the rate at which velocity
changes.
Acceleration
The acceleration that occurs in circular
motion is known as
centripetal acceleration.
A ____ is simply a push or a pull.
force
You have made a house of cards on top of
your table. Suddenly, a gust of wind blows
through an open window and your house of
cards comes tumbling down. The wind
applied _____ to your house of cards.
an unbalanced force
Two teams are having a tug of war
contest. The flag in the middle is not
moving because the two teams are
balanced.
____ is a force that opposes motion
between two surfaces that are touching.
Friction
When applying brakes on a car or a
bicycle, you are using _____ friction to
stop.
sliding
The treads on a car’s tires wear away due
to ____ friction.
rolling
A sky diver’s acceleration slows down due
to ____ friction.
fluid
A good rule to observe when around a
swimming pool is “no running.” The deck
around the pool becomes very slippery to
walk on when wet due to
fluid friction.
One of the largest forces opposing the
motion of a car is
fluid friction.
One Saturday, you go on a picnic.
Although there is a slight breeze, the
napkins stay on the tablecloth because of
static friction.
One way to increase friction is to use
sand.
____ are substances that are applied to
surfaces to reduce the friction between
them.
Lubricants
____ is a force of attraction between
objects that is due to their masses.
Gravity
Objects of any size exert a ____ force.
gravitational
____ is a measure of the gravitational
force exerted on an object.
Weight
____ is the amount of matter in an
object, and its value does not change.
Mass
Mass is measured with a
balance.
Weight is measured with a
spring scale.