Download Force and Motion

FORCE & MOTION
How is motion described and
measured?
Lesson 1:
Vocabulary Words
position
 motion
 speed

Changing Position

Position is the location of an object. It is
where something is. Some position do not
change, like your nose in the middle
of your face.
But some positions do change,
like your body, or a caterpillar
crawling on a leaf.
Changing Position
What is the position of the shortest women in
the picture?
Will her position
change?
Changing Position


The woman standing in the line will change
position. Motion is a change of position.
So when the women in the
line moves up to another
position, she demonstrates
motion.
Measuring Motion


Motion is measured by speed.
Speed is how far something moves over a
certain amount of time.
A radar gun measures
the speed of moving
cars.
Measuring Motion

To find the speed of an object. You need to
measure the distance and time of the object.
distance = the change in an object’s position
time = how long it takes the object to move to
that position.
distance
÷ time
= average speed
Measuring Motion

Example: Find the average speed of
a car if it has traveled 300 km in 5
hours.
Remember:
distance ÷ time = average speed
300 km ÷ 5 hr = _________
Comparing Speeds


Speed may change from moment to moment.
Look at the horses below. The speeds of these
two horses are different.
Comparing Speeds

Look at this video and compare the speeds of
the two horses while they race.

http://www.youtube.com/watch?v=qNR5wDGsGc&feature=related
Displaying Data About Speed

When displaying data about speed, it best to
organize the information into either a table or a bar
graph. Check out the table and bar graph below.
Table/Chart Example
Bar Graph Example
Displaying Data About Speed

What type of data does the bar graph below display?
Displaying Data About Speed

What type of data does the chart below display?
Review Time
Review Questions






What are the 2 measurements you need to find
the average speed of something?
Explain the difference between motion and
position.
Some things such as you nose, do not change
____, while others, such as cars do change.
How is a bar graph different from a data table?
Define speed.
Share with a partner one thing you learned
today.
How do forces affect motion?
Lesson 2:
Vocabulary Words
velocity
 acceleration
 force
 inertia

Glencoe Physical Science
Velocity
Velocity is the speed and the direction of an
object. When the speed and direction of two
objects are the same their velocity is the same.
What the velocity?
If a train is going 55
miles per hour, traveling
east. What the velocity?
If a rocket is going 115
miles per hour, traveling
north. What the velocity?
The velocity is 55 miles per
hour, east.
The velocity is 115 miles
per hour, north.
Changing Velocity


Objects stop and start. They slow down and speed up.
They turn. These are examples of acceleration.
changing direction
changing speed
Acceleration is any change in speed or the direction of
an object in motion.
Force and Acceleration
more force = more acceleration

Pushes and pulls are forces. Forces can change an
object’s speed or direction. Forces can change an
object’s acceleration. The direction an object moves
depends on the direction of the force.
Mass and Acceleration
Which is easier to push?
OR

A bike of course, that’s because a car has more mass. It
takes more force to change the speed or direction of an
object with a large mass than one with a small mass. The
reason mass has an effect is called inertia.
Mass and Acceleration
Let’s Watch a Video on Inertia
Study Jams
http://studyjams.scholastic.com/studyja
ms/jams/science/forces-andmotion/inertia.htm
Mass and Acceleration

Inertia is a property of matter that keeps an
object from changing speed or direction unless
a force acts on it.
The more mass an
object has, the more
inertia it has.

Review Time
Review Questions






What 2 things do you need to know in order to
find the velocity?
Explain the difference between acceleration and
force.
Both ____ and ____ depend on mass.
What causes an object’s speed or direction to
change?
Define momentum.
Share with a partner one thing you learned about
force and motion.
How does gravity affect motion?
Lesson 3:
Vocabulary Words
gravity
 gravitation
 weight
 friction

Natural Forces

You use natural forces all the time. When you
walk, you use the force of your muscles. You
use the forces of magnets and electricity in
machines.
Gravity

Gravity is the force that pulls you toward Earth. It is
an example of gravitation. Gravitation is a force that
acts between all objects.
Gravity
Sir Isaac Newton

Gravity is the force that pulls you toward Earth. It is
an example of gravitation. Gravitation is a force that
acts between all objects.
Gravity

Without gravity, we would not be able to walk on
the ground as we do. We would float like these
people. Check out the water!
Weight

Weight is the force of
gravitation that pulls on
an object.


You measure weight in
newtons (N) using a scale.
1 newton = weight of an
Weight

Mass is the amount
of matter in an
object.

You measure mass
on a balance. The
unit of mass is the
gram. (g)
Friction


Friction is the force against two things that
rub against each other.
Fiction can slow down and stop the motion of
things that touch each other. Friction also
makes heat.
Friction

Which pictures are showing friction being used?
1.man sleeping
2.rubbing hands together
Friction

Which pictures are showing friction being used?
3. car tire spinning
4. skating on the street
Review Time
Review Questions







Gravity, gravitation, and friction are ______.
Explain gravitation.
_____ opposes motion between touching objects.
How is mass different from weight?
Define friction.
How do we use natural forces everyday?
Share with a partner one thing you learned about
force and motion.