Download Newton`s 3 rd Law of Motion

The Man’s
Jeopardy
Learning Objectives
1.
2.
Describe what a force is.
Describe how balanced and unbalanced forces are
related to an object’s motion.
3. Describe friction and identify the factors that determine the
frictional force between 2 objects.
4. Identify the factors that affect the gravitational force
between two objects, and describe how they affect this
force.
5. Explain why objects accelerate during free fall (by
describing how gravity affects falling objects).
6. Apply Newton’s 1st Law of Motion to real world examples.
7. Apply Newton’s 2nd Law of Motion to real world
examples.
8. Apply Newton’s 3rd Law of Motion to real world examples.
9. Explain how an object’s momentum is conserved &
calculate momentum.
10. State the law of conservation of momentum.
RULES
1. There will be round robin play and all
questions will be all-play except for the
daily doubles.
2. The teams who answers correctly win the
point value of the question.
3. If a team answers a daily double
incorrectly, then that team will lose the
number of points they bid, and any other
team can “ring in” by raising their hand
and answer at that point.
Let’s
4. There are two daily doubles available. play
Forces & Gravity Newton’s Newton’s 3rd Law &
Friction
Laws 1&2
Momentum
100
100
100
100
200
200
200
200
300
300
300
300
400
400
400
400
500
500
500
500
Final Jeopardy
Forces & Friction for 100
Which of the following is NOT an example of
exerting a force: pushing a button, punching the
PSU mascot, running to school? What effect do
unbalanced forces have on an object’s motion?
Running to School (not exerting a force)
Unbalanced forces change an object’s motion.
Forces & Friction for 200
An object is falling toward the Earth at 9.3
m/s/s. Why is the object not falling at 9.8
m/s/s? What type of force resists the
object’s motion in the opposite direction?
Air Resistance
Friction
Forces & Friction for 300
What force typically causes momentum to
seem like it was NOT conserved?
Example- the collision of two hockey
players.
Friction
Forces & Friction for 400
Give an example of how decreasing
friction is helpful.
Oiling a machine or bike, waxing a
snowboard, using a cart with wheels to
move an object
Forces & Friction for 500
Using the diagram below, what direction is the
net force on the object? What is the net force?
How could you balance the forces on the object?
150 N
200 N
Down, 50 N, Increase the upward force by 50 N
Gravity for 100
The force that acts on all objects on Earth
and is the only force acting on an object in
free-fall is ___________.
Gravity
Gravity for 200
How can the gravitational attraction
between 2 objects be decreased?
Lower the mass and spread the objects
further apart.
Gravity for 300
Planetary Body
Mass (x 1024 kg)
Gravitational Pull
(relative to Earth)
Pluto
0.0013
0.1
Earth’s Moon
0.07
0.2
Mars
0.64
0.4
Earth
5.98
1.0
Jupiter
1900
2.4
The Sun
1,989,000
7.1
Suppose a planet with a mass of 100.5 x 1024 kg was
discovered. Based upon the data above, what is a possible
value for the gravitational pull of this new planet?
Any value from 1.1 to 2.3 would be correct. The best
values would be between 1.1 and 1.5.
Gravity for 400
Bob and Joe believe that heavier objects fall faster.
They design an experiment to test out their prediction.
What is their hypothesis? What is the independent or
manipulated variable? What is the dependent
variable? What are 2 variables that Bob and Joe
should try to keep constant?
Hypothesis- Heavier objects fall faster.
Ind. Variable- The weight or mass of the objects
Dep. Variable- Time it takes for the object to hit the
ground OR acceleration
Constants- Height of the drop, air/wind resistance (if
possible), same timer or timekeeper, etc.
Gravity
DAILY DOUBLE!
Three satellites are orbiting the Earth. The
distance from Earth is 6,000 km for Satellite
A; 10,000 km for Satellite B; and 35,800
km for Satellite C. Which one would Earth
have the greatest attraction for? Explain
why.
Satellite A because it’s the closest.
Newton’s Laws 1 & 2 for 100
The ability of an object to resist a change in
motion is called ___________.
Inertia
Newton’s Laws 1 & 2 for 200
What types of objects have the greatest
inertia? What do objects in motion tend to
do? What do objects at rest tend to do?
Heavier objects
Objects in motion tend to stay in motion
Objects at rest tend to stay at rest
Newton’s Laws 1 & 2 for 300
An object accelerates at 4 meters per second2 for a
force of 20 N. How much force is needed for an
acceleration of 2 m/s/s for the same object? If the
amount of force on a heavy object is the same as
the amount of force on a lighter object, then which
object will have the lower acceleration?
Half the acceleration for a constant mass = half the
force, so 10 N
The heavier object will have the lower
acceleration.
Newton’s Laws 1 & 2 for 400
A 100 kg person is skydiving. What is the force of
gravity (or weight) acting on the skydiver?
F=mxa
F = 100 kg x 9.8 m/s/s
F = 980 N
Newton’s Laws 1 & 2
DAILY DOUBLE!!!
Give two real world examples of Newton’s 1st
Law (you may do this verbally instead of writing
it down).
A car stops and your body moves forward, a car
takes off and your body moves backward, etc.
Newton’s 3rd Law & Momentum
for 100
According to Newton’s 3rd Law, for every action
there is an _________ and ________ reaction.
For every action there is an equal and opposite
reaction.
Newton’s 3rd Law & Momentum
for 200
What are the action-reaction forces when a
carpenter hammers a nail?
Action = hammer striking the nail
Reaction = nail pushes back on the hammer
Newton’s 3rd Law & Momentum
for 300
How is momentum calculated?
True or False. Change the underlined word to
make it true. The momentum of an object is in
the OPPOSITE direction of that object’s
velocity.
Momentum = mass x velocity
False, momentum is in the SAME direction as
the object’s velocity.
Newton’s 3rd Law &
Momentum for 400
If the total momentum after a collision is 10 kg x
m/s, then what was the total momentum before
the collision? Explain how you know.
10 kg x m/s because momentum is conserved
(remains the same and is not lost, only
transferred)
Newton’s 3rd Law & Momentum
for 500
How can an object’s momentum increase?
How does an object’s mass affect its
momentum?
Moving faster or higher velocity
Greater the mass, the higher the
momentum
Force Diagram
Draw a force diagram for a person pushing a
large oven up a ramp toward the left. Label
all of the forces acting on the box using arrows
of the correct length.