Download Motion and Forces Study Guide VOCABULARY Position – An

Motion and Forces Study Guide
VOCABULARY
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Position – An objects location relative to another object (the reference point) plus the distance
from the other object.
Force – A push or pull.
Friction – a force that opposes motion between two surfaces that are touching.
Gravity – a pull that attracts objects to each other. This is a force.
Speed – a measure of how fast an object is moving
Unbalanced forces – change the rate and direction of the motion of objects
Rate of motion – the speed of the object
Balanced forces – equal in strength but opposite in direction.
Air resistance – type of friction between an object and air.
Compass – an instrument used to determine direction
Direction of motion – The course of path that an object is moving.
Distance – path which an object moves
Distance-time graph – a visual comparison of distance – time data
Fluid – substances capable of flowing freely: liquid, gases
Lubricant – substance used to reduce friction
Lubrication – adding a lubricant to reduce friction
Magnetism – a force that acts at a distance and cannot be seen
Mass – a measure of how much matter an object has.
Magnetic Poles – where the magnetic field is strongest
Surface texture – the appearance and feel of the surface of an object
Time interval – a space of time between events
Magnetism
What can forces do? They can make things move faster, slower, stop, or change direction.
List three forces that can affect motion. Magnetism, gravity, friction
What do we call materials that create the force of magnetism? Magnets
How is a compass affected by the Earth’s magnetism? The needle moves
When like poles (S-S or N-N) of magnet are near each other the magnetic force cause the poles
to ____repel_____________ each other.
When unlike poles (S-N or N-S) of magnets are near each other the magnetic force cause the
poles to ____attract_______________ each other.
The closer the objects, the ________greater_________ the magnetic force.
Where, on a magnet, is the force greatest? At the poles
Gravity
1) Why do we not notice the attraction of gravity on everyday objects for example your desk and
chair? Because it is only noticeable if one of the objects is very large like a planet, moon, or the
Sun.
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Why is the force of gravity between Earth and anything on it so noticeable? Because the mass
of the Earth is so large. The pull of Earth’s gravity makes any object fall to the ground.
3) How does the Moon’s gravity affect the Earth? It causes the water in the oceans to move
toward the Moon.
4) How does the Earth’s gravity affect the Moon? It keeps the Moon moving around the Earth.
5) How does the Sun’s gravity affect the Earth? It keeps the Earth moving around the Sun.
Friction
1) How can we see the effect of friction on two objects as one object slides across the other’s
surface? As an object slides across a surface and slows down
2) How could friction be increased? Make the surface rougher and or make the surfaces press
together harder
3) How can we reduce friction? Use lubricants, making surfaces smoother, using rollers
4) Give three examples of lubricants. Motor oil, wax, grease
5) Frictions occurs in ______liquids_____ and ___gases________ as well as between solids.
6) What would happen if we did not have friction? It would be very hard to slow or stop the
motion of objects.
Position
1) What are some words that are used to describe position? Above, below, beside, behind, ahead
of
2) What happens when objects move? The distance from the reference point changes.
Direction
1) How can we determine direction? By reading a compass.
2) What are the terms used to describe direction on a compass? North, south, east, west
3) Name other terms used to describe direction relative to another object? Right, left, forward,
toward
4) Name terms used to describe direction relative to Earth? Up, down
Balanced and Unbalanced Forces
1) How many forces can act on an object at the same time? Several (more than two)
2) Which force changes the motion of objects? Unbalanced
3) Why do unbalanced forces change the motion of objects? Because they do not have another
force of equal magnitude and opposite direction off-setting it.
4) Describe how unbalanced forces can change the rate or direction of motion in these different
ways:
The car is at rest. If an unbalanced force acts on the car. The
car will move in the same/ opposite direction of the force.
The car is at rest. A stronger unbalanced force acts on the
can. The can will move slower/faster.
The car is in motion. An unbalanced force acts on the car. Describe the effect of the unbalanced force
on the car.
Unbalanced Force
Direction of car.
The car will _speed up . _____________________
Direction of car.
Unbalanced force
The car will slow down or stop._______________________________________________
Unbalanced
force
Direction of car
The car will turn or change direction.__________________________________________
Variables that influence the effect of friction
1) What variables could influence friction? Texture of a surface, amount of surface area,
lubrication
2) Rough surfaces create _more__ friction and smooth surfaces create _less___ friction.
3) The amount of surface area affects the friction between objects in _liquids_ and __gases__.
4) Give an example of surface area in gases. A parachute’s size – air resistance
5) Give an example of surface area in liquid. Boat gliding through water
6) Are solids affected by surface area? No
7) What would happen to machines with moving parts if the moving parts where not lubricated?
The moving parts would slow down or stop.
Graphs
1) All graphs should include the following parts. Title, label the axes, placement of intervals,
placement of the independent and dependent variable
2) How do the terms “DRY-MIX” help you with a graph? They help you remember which axes are
the dependent and independent.
3) Answer the questions about graphs!
Motion affected by change in force or mass
Truck A
Truck B
1) Truck A and B have the same mass. Truck B is acted on by a greater force than truck B. Which
truck will have the greatest change in speed over the same period of time? Truck B
Truck
Car
2) The truck and car have different masses but have the same amount of force applied to each.
Which will have the greater change in speed over the same period of time? The car