Download Forces and Motion Study Guide

Forces and Motion Study Guide
1. Speed is the rate of change over time.
2. What is momentum? What is The Law of
Conservation of Momentum? Momentum =
mass x velocity. LOCOM = the momentum of
a system is constant if there are no outside
forces acting on the system.
3. What is inertia? Give an example. An objects
resistance to motion. A rock has more inertia
than a pebble.
4. What is a force? A push or a pull
5. What are balanced and unbalanced forces? Give an
example. Balanced forces have a net force of zero,
unbalanced do not have a zero net force when added
or subtracted. Balanced = an object at rest,
Unbalanced = an object in motion
6. When a toy truck collides with a toy car what happens
to the momentum of the car and the
truck before
and after the collision? Momentum of the system
stays the same before and after the collision because
of The Law of Conservation of Momentum.
7. What type of force does Earth exert on a ball thrown
into the air? Gravitational Force *When the only
force acting on an object is gravity the object is in
free fall.
8. How is velocity different than speed? Velocity is a
measure of motion plus direction and speed is just a
measure of motion, no direction is given.
9. What is acceleration? a measure of change in
velocity
10.Describe three different ways a change in
acceleration can occur? increase acceleration,
decrease acceleration, change direction
11.What causes a leaf and an acorn to fall at
different rates? Air resistance. There is a greater
amount of air resistance acting on the leaf
because the leaf has more surface area than the
acorn
12.Explain the action and reaction forces that occur
as you walk? Action Force = you push your foot
down on the Earth when you’re moving forward.
Reaction Force = the Earth pushes back up on
your foot.
13.When graphing an object in motion what
goes on the horizontal axis? Vertical axis?
horizontal axis = time, vertical axis = distance,
speed, or velocity depending on what your
graphing
14.What is the average speed of an object that
travels 100 meters in 5 seconds? 20 m/s
15.What is the upward force on an object falling
through the air? Air Resistance
16.What are vector arrows? What do they tell
you about objects in motion? Arrow that
show forces acting on an object in a diagram.
Strength and direction
17. Draw a sketch of a book sitting on a table. Draw
vector arrows to show forces acting on the book.
Label the forces acting on the book.
18. Whenever an object is in motion what is opposing the
motion? Friction
19. What is gravitational force? What two things affect
the strength of gravitational force between two
objects? GF = attraction between all objects, mass
and distance of two objects affect gravitational force
20. Define motion? a change in position of an object over
time
21.What is static friction? Give an example. Friction
that occurs between two or more solid object
that are NOT moving relative to each other. Ex:
pencil sitting on a desk
22.What is rolling friction? Give an example.
Friction that occurs when a round surface rolls
over another surface. Ex: a ball rolling down a
street or pushing a grocery buggy.
23.What is sliding friction? Give an example.
Friction created between two objects sliding or
rubbing against each other. Ex: rubbing your
hands together or a box sliding across the floor.
24.What 3 things are needed to determine the
velocity of a moving truck? distance moved,
time it took to move given distance, and
direction
25.What is the term for a rate of change in velocity?
Acceleration
26.What is the measure of inertia? mass
27. Speed measures change in what? distance over
time
28.What is the amount of matter in an object
called? mass
29.What is average speed? Total distance traveled
over total time. *On a long trip you might slow
down and speed up along the way. When
someone asks how fast you drove you probably
give them your average speed.
30.What is instantaneous speed? On the long trip
instantaneous speed is the speed you were
going at one specific moment in time.
31. Suppose that Boy A exerts a force of 3000 Newtons on the
box and Boy B exerts a force of 5000 Newtons in the
opposite direction.
a. Draw arrows showing the individual and combined forces
of the box in the picture below.
b. What is the combined force (net force) on the box?
__2000 Newtons_______________
c. Are the forces balanced or unbalanced? __unbalanced,
so the box is probably moving_
3000 N
A
5000 N
2000 N
B
32. Could there ever be a case when Boy A and Boy B are both
exerting a force on the box but the box doesn't move? Yes, if the
forces are equal and in opposite directions.
Distance (m)
Speed (m/s)
20
15
10
5
0
1
2
3
4
5
6
7
8
Time (s)
33.Describe the object’s motion the first 4
seconds? Moving forward at a constant rate
Describe the object’s motion at 5 seconds? Not
moving
Describe the object’s motion the last 3 seconds?
Going backwards
36. Describe the object’s motion in each of the
following graphs.
Moving a constant speed, speed
stays the same.
Graph A
Graph B
Graph C
Speed is increasing at a constant
rate.
Speed is decreasing at a constant
rate.
37. What is Newton’s 1st Law of Motion? Give an example. An
object at rest will remain at rest unless acted on by an
outside force, also known as law of inertia, deals with
balanced forces. Ex: table cloth trick
38. What is Newton’s 2nd Law of Motion? Give an example.
The acceleration of an object is dependent upon two
variables - the net force acting upon the object and the
mass of the object, F=MA Ex: Increasing the mass of a car
will increase its momentum when in motion
39. What is Newton’s 3rd Law of Motion? Give an example.
For every action there is an equal and opposite reaction,
deals with action and reaction forces. Ex: For a bird to fly
upwards, it must flap it’s wings in a downward motion
(action force). The air under the bird is compressed and
pushes back up on the bird (reaction force).
40. What is Centripetal Force? Give an example. Any motion
in a curved path represents accelerated motion, and
requires a force directed toward the center of curvature
of the path. Ex: Ice skater spinning