Matter in MotionMatter in Motion

When an object changes position over When an object changes position over time when compared with a reference time when compared with a reference

point, the object is inpoint, the object is in

motion.motion.

The rate at which an object moves is The rate at which an object moves is itsits

speed.speed.

The speed of an object in a particular The speed of an object in a particular direction is the object’sdirection is the object’s

velocity.velocity.

____ is the rate at which velocity ____ is the rate at which velocity changes.changes.

AccelerationAcceleration

The acceleration that occurs in circular The acceleration that occurs in circular motion is known asmotion is known as

centripetal acceleration.centripetal acceleration.

A ____ is simply a push or a pull.A ____ is simply a push or a pull.

forceforce

You have made a house of cards on You have made a house of cards on top of your table. Suddenly, a gust of top of your table. Suddenly, a gust of wind blows through an open window wind blows through an open window

and your house of cards comes and your house of cards comes tumbling down. The wind applied _____ tumbling down. The wind applied _____

to your house of cards.to your house of cards.

an unbalanced forcean unbalanced force

Two teams are having a tug of war Two teams are having a tug of war contest. The flag in the middle is not contest. The flag in the middle is not moving because the two teams aremoving because the two teams are

balanced.balanced.

____ is a force that opposes motion ____ is a force that opposes motion between two surfaces that are between two surfaces that are

touching.touching.

FrictionFriction

When applying brakes on a car or a When applying brakes on a car or a bicycle, you are using _____ friction to bicycle, you are using _____ friction to

stop.stop.

slidingsliding

The treads on a car’s tires wear away The treads on a car’s tires wear away due to ____ friction.due to ____ friction.

rollingrolling

A sky diver’s acceleration slows down A sky diver’s acceleration slows down due to ____ friction.due to ____ friction.

fluidfluid

A good rule to observe when around a A good rule to observe when around a swimming pool is “no running.” The swimming pool is “no running.” The deck around the pool becomes very deck around the pool becomes very slippery to walk on when wet due toslippery to walk on when wet due to

fluid friction.fluid friction.

One of the largest forces opposing the One of the largest forces opposing the motion of a car ismotion of a car is

fluid friction.fluid friction.

One Saturday, you go on a picnic. One Saturday, you go on a picnic. Although there is a slight breeze, the Although there is a slight breeze, the

napkins stay on the tablecloth because napkins stay on the tablecloth because ofof

static friction.static friction.

One way to increase friction is to useOne way to increase friction is to use

sand.sand.

____ are substances that are applied to ____ are substances that are applied to surfaces to reduce the friction between surfaces to reduce the friction between

them.them.

LubricantsLubricants

____ is a force of attraction between ____ is a force of attraction between objects that is due to their masses.objects that is due to their masses.

GravityGravity

Objects of any size exert a ____ force.Objects of any size exert a ____ force.

gravitationalgravitational

____ is a measure of the gravitational ____ is a measure of the gravitational force exerted on an object.force exerted on an object.

WeightWeight

____ is the amount of matter in an ____ is the amount of matter in an object, and its value does not change.object, and its value does not change.

MassMass

Mass is measured with aMass is measured with a

balance.balance.

Weight is measured with aWeight is measured with a

spring scale.spring scale.