Falling Safely

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  • Created by: Lily04
  • Created on: 13-06-17 11:46
Complete the sentence: when a skydiver jumps, he initially ACCELERATES due to the force of .....
Gravity
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Fill in the gaps: as he falls, he experiences the ....... in the ..... direction. At this point, ....... is ....... than the frictional force of air resistance, so he continues to .....
As he falls, he experiences the FRICTIONAL FORCE OF AIR RESISTANCE in the OPPOSITE direction. At this point, WEIGHT is GREATER than the frictional force of air resistance so he continues to ACCELERATE.
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As the speed of the parachutist increases, what increases too?
Air resistance acting on him
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How does the parachutist end up falling at a constant speed, I.e how does he reach his TERMINAL SPEED
Air resistance increases until it's equal to the weight. The resultant force now acting on him is 0 and his falling speed becomes constant as forces are balanced- this speed is called the terminal speed.
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When the parachute opens, why do unbalanced forces act again?
Because the upward force of air resistance is greatly increased and is bigger than weight
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What force decreases his speed?
Increase in the frictional force of air resistance
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Explain how a NEW TERMINAL SPEED is reached.
Frictional force of air resistance decreases until its equal to the weight. The forces acting are once again balanced and therefore falls at a steady speed, this is the NEW TERMINAL SPEED
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True or false? The first terminal speed is slower than the new terminal speed
FALSE the second terminal speed is slower than the first
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If the forward force is bigger than the backward force what happens to an object in terms of movement?
Increase speed
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In terms of balancing of forces, what causes a decrease in speed?
If the forward force is smaller than the backward force.
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Terminal speed occurs when....
DRAG=WEIGHT
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What two factors increase the DRAG experienced by an object?
Increase the area and speed
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Why is the acceleration the same for any object at a given point on the Earths surface?
Due to gravity
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Give 2 ways frictional forces can be reduced
Friction forces between moving parts of a machine can be reduced by LUBRICATING them. STREAMLINING their shapes
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What is gravitational field strength and what is it measured in?
Force on each kilogram of mass due to gravity- measured in N/kg
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Give 3 things that are true about acceleration due to gravity/ gravitational field strength
Is unaffected by atmospheric changes, varies slightly at different points on the Earth's surface, will be slightly different on the top of a mountain or down a mineshaft
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True or false? On the moon, where there is no atmosphere, this is no drag force on falling objects. They all fall with the same acceleration.
TRUE
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Other cards in this set

Card 2

Front

Fill in the gaps: as he falls, he experiences the ....... in the ..... direction. At this point, ....... is ....... than the frictional force of air resistance, so he continues to .....

Back

As he falls, he experiences the FRICTIONAL FORCE OF AIR RESISTANCE in the OPPOSITE direction. At this point, WEIGHT is GREATER than the frictional force of air resistance so he continues to ACCELERATE.

Card 3

Front

As the speed of the parachutist increases, what increases too?

Back

Preview of the front of card 3

Card 4

Front

How does the parachutist end up falling at a constant speed, I.e how does he reach his TERMINAL SPEED

Back

Preview of the front of card 4

Card 5

Front

When the parachute opens, why do unbalanced forces act again?

Back

Preview of the front of card 5
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