BGS - 10. Force and Motion Flashcards
Vector Quantities
A vector quantity is one which has both a value and a direction.
If there is only a value, this is a scaler quantity
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Displacement
The distance travelled in a straight line
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Velocity
Speed in a particular direction
An aircraft in a climb has both;
Vertical Velocity (rate of climb)
and
Horizontal Velocity (groundspeed)
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Acceleration
An objects rate of change of velocity either in direction or speed
Accelerating in a straight line or slowing down are changes in acceleration.
In a car, going around a sharp corner pushes us out to the side through ‘cornering forces’.
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Force
A stationary object will remain stationary until some external force causes it to move.
If an object is already moving, it will continue to move in the same direction at the same speed until some external force causes it to change
Newtons FIRST LAW of motion
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Force
In an aircraft we have lift and gravity.
If gravity is the same as lift, the resultance force is 0
However, if lift is more than gravity, the plane will have a resultant force
Resultant Forces and Motion
Force = Mass x Acceleration
F = M x A
or
M = F / A
or
A = F / M
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Resultant Forces and Motion
Applying a force to an object will cause it to start accelerating.
The object will accelerate in the direction of the resulting force.
The rate of acceleration will depend on the mass of the object and the size of the force
Doubling the force DOUBLES the acceleration
Doubling the mass HALVES the acceleration
Newtons SECOND law of motion
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Resultant Forces and Motion
Unit of measurement of force
Newton (N)
1N is the force required to accelerate a mass of 1kg by 1m/sec²
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Opposing Forces
For each action, there is an equal and opposite reaction
Newtons THIRD law of motion
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Oppsing Forces
Gravity pulls you towards the center of the Earth.
The groud exerts a force in the opposite direction, oppsing you.
Gravity prevents you floating off as a result of the ground pushing against your feet, but the ground stops gravity boaring you into the ground
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Newtons Laws Reminder
Law 1
Objects at rest or in motion stay that way unless a force acts on them
Law 2
Forces are related to mass and acceleration
Law 3
Every action has an equal and opposite reaction
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