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32 Cards in this Set
- Front
- Back
Speed definition |
- Measure of how fast something is moving - Rate at which distance is covered |
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What is instantaneous speed? |
The speed at any instant. |
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What is average speed? |
Total distance covered divided by time |
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Velocity definition |
Speed in a given direction Eg. ✈ travelling 800km.k^-1 NE |
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When is velocity constant? |
Only when speed and direction is constant |
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Average velocity |
Total distance covered divided by time Units= m.s^-1 |
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Acceleration Definition |
The rate at which velocity is changing |
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Calculating acceleration |
Acceleration = final velocity - initial velocity over time Units = m.s^-2 |
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When is an object considered to be accelerating? |
When its speed is increasing or decreasing (negative acceleration or deceleration) and/or when its direction is changing |
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What affects the acceleration of a falling object? |
Air resistance |
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What is free fall? |
When there's no air resistance, and gravity is the only force affecting the object |
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What is the measure of gravity? |
9.8m.s^-2 (acceleration on free fall) |
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Formula of velocity on free fall |
v=gt |
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Formula of distance on free fall |
1/2 gt^2 |
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What is force |
Any push or pull |
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What is friction |
Force that acts between materials that are moving past each other |
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What causes friction |
From the irregularities in the surfaces of sliding objects |
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What is inertia |
Resistance to change in its state of motion |
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Law of inertia states: |
An object will stay in motion or at rest, unless a force is exerted upon it. |
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What is mass |
Measure of the inertia of an object |
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What is weight |
Measure of gravitational force that acts on the material |
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Converting m.s^-1 to km.h^-1 (velocity) |
Divide 3.6 |
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What is the standard units |
a= m.s^-2 w/f= N mass= kg s= m t= s v= m.s^-1 |
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What produces acceleration |
Forces |
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What is net force |
Combination of all the forces that act on the object |
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Second law states |
Acceleration is directly propotional to the magnitude of the net force and inversely propotional to the mass |
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Pressure equation |
Pressure = Force over area of application |
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What is pascal |
Measured in Newton per square metre |
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Terminal velocity |
When the air resistance of a falling object equals the weight of the object, the net force is zero l, acceleration terminates |
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3rd law states |
Every action has an equal and opposite reaction |
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What are two forces called |
Action and reaction |
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Free fall explained |
All objects on Earth has the same acceleration regardless of mass due to the weight being the only net force acting on the object |