# Unit 1 mechanics (G481) motion

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- Created by: Elly
- Created on: 02-01-13 10:15

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- Motion
- scalars
- a quantity with magnitude but not direction
- e.g. potential difference, speed, pressure, distance

- Free fall
- g=9.81ms^-2
- Trap door method
- electromagnet just supports a steel ball
- when current through the electromagnetis switched off theball starts to fall and the clock is triggered.
- balls falls onto trap door
- when trap door breaks the clock is stopped.
- distance of fall is measured and so is the time taken.
- Repeats
- electromagnet just supports a steel ball
- when current through the electromagnetis switched off theball starts to fall and the clock is triggered.
- balls falls onto trap door
- when trap door breaks the clock is stopped.
- distance of fall is measured and so is the time taken.
- Repeats

- Repeats

- distance of fall is measured and so is the time taken.

- when trap door breaks the clock is stopped.

- balls falls onto trap door

- when current through the electromagnetis switched off theball starts to fall and the clock is triggered.

- electromagnet just supports a steel ball

- Repeats

- distance of fall is measured and so is the time taken.

- when trap door breaks the clock is stopped.

- balls falls onto trap door

- when current through the electromagnetis switched off theball starts to fall and the clock is triggered.
- theory
- s=ut+1/2at^2 . u is 0 as ball starts from rest.
- this gives s=1/2gt^2 and hence g=2s/t^2.
- a graph of s against against t^2 will have a gradient of g/2.

- this gives s=1/2gt^2 and hence g=2s/t^2.

- s=ut+1/2at^2 . u is 0 as ball starts from rest.
- Random uncertainty
- em current too large cause a delay in releasing ball. current must only just support ball.
- If distance is too large or ball to small air resistance may have a noticeable effect.
- ensure that distance is measured accurately from base of ball to trap door not the electromagnet to door.

- electromagnet just supports a steel ball

- Vectors
- resolving
- horizontal and vertical components

- Calculations
- Trigonometry
- the length of the hypotenuse AC is 55.0mm and angle next to right angle is 72*.
- This makes the side adjacent to the angle 55.0xCos72*=17.0mm
- and the side opposite to the angle =55.0xSin72*=52.3mm

- the length of the hypotenuse AC is 55.0mm and angle next to right angle is 72*.
- Pythagorus
- A llorry's load hass a weight of 40000NN and it is being pulledd along by a horizontal force of 15000N what is the resultant of these two forces?
- Resultant^2= (4.0x10^4)^2 + (1.5x10^4)^2 = 18.25x10^8 so resultant=4.27x10^4N

- A llorry's load hass a weight of 40000NN and it is being pulledd along by a horizontal force of 15000N what is the resultant of these two forces?

- Trigonometry
- a quantity with both magnitude and direction
- e.g. electric current, velocity, displacement, acceleration, force.

- resolving
- constant acceleration equations
- s u v a t
- s = displacement
- m

- u = initial velocity v= end velocity
- ms^-11

- a = acceleration
- ms^-2

- t = time
- s

- s = displacement
- v=u+at
- s=1/2(u+v)t
- s=ut+1/2at^2
- v^2=u^2+2as

- s u v a t
- graphs of motion
- Displacement-time graphs
- Gradient = velocity

- velocity-time graphs
- gradient represents accelerration
- Untitled

- Displacement-time graphs

- scalars
- This makes the side adjacent to the angle 55.0xCos72*=17.0mm

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