Transcript Factors That Affect Motion

Factors That Affect Motion
Objects are made of matter
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Matter is the stuff that makes up everything in the
universe.
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Mass is the amount of matter in an object.
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The mass of an object affects it’s motion.
Inertia affects motion
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Inertia is an objects resistance to change motion. The
greater the mass of an object, the greater the inertia the
object will have.
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Example- It is hard move a big object like a semi-truck. It
is also hard to stop a semi-truck when it has started
moving. This is due to the fact that a semi-truck is very
mass and has a lot of inertia.
Momentum
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Momentum is the mass and velocity of an object
multiplied together. Greater mass and speed cause
moving objects to have greater momentum.
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Examples
– A human that weighs 160 pounds and is running has more
momentum then a human that weighs 160 pounds that is walking.
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A truck traveling at 60 mph has a more momentum than a motorcycle driving
at 60 mph.
Which object would have greater momentum?
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120 lb cheetah running at 60 mph
2000 lb car traveling at 60 mph
3000 lb Jet traveling at 2000 mph
3000 lb truck traveling at 80 mph
2 ounce tennis ball traveling 60 mph
12 lb shot put traveling at 20 mph
Friction is a force
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Friction is a force that causes objects to stop moving. Friction
happens whenever two objects rub together.
You can feel the friction in the form of heat when you rub your hands
together.
Examples of Friction – Air resistance, When you cannot run through
the water, a ball rolling to a stop.
What is the real definition of work?
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Work – Using a force to move an object over a certain
distance.
In order to do work you must exert an effort.
Examples of work – Moving your pencil across your
paper. Picking up your books and taking them to math
class. Running a lap on the track.
This is not an example of work.
What is energy
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Energy is the capacity to do work.
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Energy comes in many different forms.
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Examples of energy.
Food
Electricity
Heat
Light
How do humans use energy
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Nearly everything you do is considered work. In order
to do this we need energy. Humans get their energy
from the food we eat.
Examples of how we use energy through work.
Getting dressed, walking up and down stairs, cleaning your room.
Can you think of any other ways you use energy to do work.
Why do we need machines
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A machine is something that replaces human effort.
Machines make doing work easier.
A car helps us travel far distances quickly.
A knife helps cut food easily.
Can you think of any machines that reduce effort for the
work we have to complete.
How do machines use energy?
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Different machines require different types of energy.
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A blender requires electrical energy.
A car requires heat energy from burning gasoline.
A remote control requires chemical energy from batteries.
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Questions you may see on the EOG
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What is the tendency of an object to remain at rest or stay in motion?
a. inertia
b. gravity
c. friction
d. magnetism
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What is changed when the speed and mass of an object are increased?
a. friction
b. gravity
c. inertia
d. momentum
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A soccer ball rolls across a grassy field and comes to a stop. What caused the soccer ball to stop?
a. inertia
b. friction
c. gravity
d. magnetism