# Physics

- Created by: Ashleigh
- Created on: 30-11-12 18:31

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- Physics
- Resultant Force
- An object has many different forces adding upon it.
- These can be added up into a single force: the resultant force.

- When all the forces are balanced, the resultant force is zero.
- A stationary object remains stationary.
- Moving objects keep moving at the same pace and in the same direction.

- When all the forces are not balanced, the resultant force is not zero
- In this case the object accelerates in the direction of the resultant force.
- A stationary object begins to move in the direction of the resultant force.
- A moving object will speed up, slow down or change direction depending on the resultant force.

- Force, Mass and Acceleration.
- Size of force: Obejcts accelerate in the direction of resultant force
- Bigger the resultant force the bigger the acceleration.
- Doubling the size of the resultant force doubles the acceleration.

- Bigger the resultant force the bigger the acceleration.
- Mass: A force on a large mass will accelerate it less than the same force on a smaller mass.
- Size of force: Obejcts accelerate in the direction of resultant force
- Bigger the resultant force the bigger the acceleration.
- Doubling the size of the resultant force doubles the acceleration.

- Bigger the resultant force the bigger the acceleration.
- Doubling the mass halves the acceleration.

- Size of force: Obejcts accelerate in the direction of resultant force
- Calculating Acceleration: A = F/M
- F = Resultant Force, Newtons (N)
- A = Acceleration of the object, Metres per seconds (M/Ssquare)
- M = Mass, Kilograms (KG)

- Size of force: Obejcts accelerate in the direction of resultant force

- An object has many different forces adding upon it.
- Forces and motion
- Distance-time graphs
- Vertical axis = distance
- Horizontal axis = time
- When an object is stationary, the line on the graph is horizontal
- When an object is moving at a steady in a straight line, the line on the graph is also straight but sloped.
- Steeper the line the greater the speed of the object.

- Calcuating speed
- Speed (m/s) = Distance travelled (m) / Time taken (s)

- Velocity-time graphs
- The velocity of an object is it's speed in a particular direction
- Two different cars will have different velocities if they are travelling at:
- The same speed but in different directions.
- The different speeds in the same direction
- different speeds in different directions

- different speeds in different directions

- Vertical axis = Velocity of the object
- Horizontal axis = time
- when an object is moving with a constant velocity, the line on the graph is horizontal
- when an object is moving with a constant acceleration, the line is straight but steep
- The steeper the line, the greater the acceleration.
- a line sloping downwards - with a negative gradient - represents an object with a constant deceleration (slowing down)

- Do not confuse
- Distance-time graphs
- Vertical axis = distance
- Horizontal axis = time
- When an object is stationary, the line on the graph is horizontal
- When an object is moving at a steady in a straight line, the line on the graph is also straight but sloped.
- Steeper the line the greater the speed of the object.

- Distance-time graphs

- Acceleration
- A = (u-v) / T
- A = Acceleration (m/ssquare)
- u = final velocity (m/s)
- v = starting velocity (m/s)
- T = time taken (s)

- A = (u-v) / T

- Distance-time graphs

- Resultant Force
- Moving objects keep moving at the same pace and in the same direction.
- You can not possiblity tell which is correct unless you know if the object is moving or not.
- A moving object will speed up, slow down or change direction depending on the resultant force.
- A stationary object begins to move in the direction of the resultant force.
- A stationary object remains stationary.

- To calcuate the gradient of the line divide the change in the vertical axis by the change in the horizontal axis

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