Transcript Go over study guide - Jefferson School District

Chapter 2 Study Guide
Answers
Question 1
What two things
are needed to
describe a
vector.
 Direction and magnitude
 Remember, force is a vector.
Force has a direction (we
show it with arrows), and the
magnitude is the strength of
the force (we measure it in
Newtons.)
Question 2
Describe
magnitude in
two different
ways.
 Size or measurement
 10 degrees
 50 yards
 20 m/s2
 25 newtons (Force!)
 Magnitude is something
you can measure.
Question 3
Identify all of the  Gravity
types of forces
 Normal
acting as you sit  Applied
in your chair.
 Balanced
Question 4
Identify all of the
types of forces
acting on
another object
that is moving.
 Gravity
 Normal
 Friction
 Inertia - maybe
 If the speed is constant and
traveling in a straight line
it is balanced.
Question 5
What happens
where forces are
balanced?
 Net force is zero
 Motion doesn’t change
 But it can be moving, just at a
constant speed and direction.
 Recall: velocity changes when an
object speeds up, slows down or
changes direction. If velocity
changes, the forces are
UNBALANCED. This is why
forces are BALANCED at a
constant speed.
Question 6
Give two
examples of
balanced forces.
 Share out your
examples.
 A car with cruise
control on. (Constant
speed).
 An object at rest.
Question 7
What happens
when forces are
unbalanced.
 Net force is NOT zero
 Velocity will change
therefore acceleration is
changing.
 Slowing down
 Speeding up
 Changing direction
Question 8
Give two
examples of
unbalanced
forces.
 Share out your
examples.
Question 8
Give two
examples of
unbalanced
forces.
 Share out your
examples.
 One team wins a game
of tug-o-war
 Any object that is
changing velocity
Question 9
Describe two ways to
increase the
magnitude of an
object’s acceleration.
 Decrease mass
 Increase force
 For example, how can she
increase acceleration?
 Reduce the amount of
weights.
 Increase force by
strengthening her muscles
Question 10
Put the law of
universal
gravitation in
your words and
give an example.
 All objects are pulled towards each
other by gravity. The force of this
pull is affected by the size of the
two objects and/or the distance
between them.
 Example (pg 97): Earth is large
enough and close enough to exert
force on us (Gravity pulls from
Earth’s core).
 As Mass increases, Gravity increases
(and vice versa)
 As distance increases, gravity
decreases (and vice versa).
Question 11
What are
Newton’s 3
laws of
motion?
 1st- Law of Inertia, objects in motion
stay in motion, objects at rest stay at
rest unless acted on by another force.
 2nd-Relationship between force, mass
and acceleration
 3rd- Every action has an equal and
opposite reaction
Question 12
When an object
is speeding up,
what direction is
force being
added?
 The same direction as
the motion of the object
Question 13
When an object
is slowing down,
what direction is
force being
added?
 The opposite direction
as the motion of the
object
Question 14
When an
unbalanced force
acts on an object
at rest, what
direction will the
object go?
 The same direction as
the force