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The Sky’s the Limit
Terms
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Acceleration
Aerodynamics
Air Pressure
Balanced forces
Drag
Force
Gravity
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Lift
Mass
Propulsion
Thrust
Unbalanced forces
Acceleration
• The rate of change of an object’s speed with
time. To speed up, an object must accelerate;
to slow down, it decelerates.
Aerodynamics
• The science that deals with the flow of air
around an object in motion.
Air pressure
• The amount of force air exerts on an object.
Balanced Forces
• Forces that do not produce motion when they
interact.
Drag
• The aerodynamic force that acts against an
object moving through air or another fluid.
Force
• A push or pull that makes an object move, or
change speed or direction if it is already
moving.
Gravity
• The force that attracts things toward the
centre of large objects. Earth's gravity causes
people and objects to have weight.
Lift
• The aerodynamic force that acts
perpendicular to the direction of motion,
causing an object to rise.
Mass
• The amount of matter in an object.
Propulsion
• A driving force that pushes an object.
Thrust
• The force that pushes a flying object forward.
An aircraft engine produces thrust that
propels the craft.
Unbalanced forces
• Forces applied at the same time that produce
acceleration when they interact.
Explain how a hot air balloon works.
• The air in a hot air balloon is heated by a propane
burner at the base of the balloon. Once the air
inside the balloon has been heated the balloon
will rise because the hot air is lighter than the
cold air surrounding the balloon. The balloons
weight is controlled by turning the burner on and
off when needed allowing the balloon to rise and
land.
The movement of a shower curtain after a
shower is turned on show Bernoulli’s
principle. Describe how it represents
Bernoulli’s Principle.
Bernoulli’s Principle
• Fast moving water gushes past the shower
curtain. As Bernoulli’s principle states, this
fast moving water will cause low pressure on
the inside part of the shower curtain.
Therefore, on the other side of the curtain is
high pressure. This high pressure pushes
against the low pressure and causes the
shower curtain to move inwards.
Explain kayakers use resistance.
• Isaac Newton put forward a law of motion. It
states that every action has an equal and
opposite reaction. As a kayak moves through
water, it pushes the water and the water
pushes back. If the rudder is turned slightly
on way or the other, the sideways angle of
resistance turns the boat. The boat must be
moving for the rudder to work – if not there is
no speed, no resistance and no force.
Name 4 facts about lift
• Lift depends on shape – lift is greater with an
airfoil-shaped wing than with a flat one.
• Lift depends on angle of attack – up to a point,
lift increases as the angle of attack increases.
• Lift depends on speed – lift increases as speed
increases.
• Lift depends on direction – lift acts
perpendicular to the direction of the objects
movement.
Why are the wings of a plane curved?
• When an airplane moves forward, air moves
backward over and under its wing. The air
moving above the wing moves more quickly
because of the curved top. As the higher
pressure air beneath the aircraft tries to move
up to the area of lower pressure, it presses up
on the plane. When the lift becomes greater
than the force of gravity, the airplane rises
into the air.