2008-01-05 02:07:23

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This classroom mainly deals with Forces and Motion but if you have questions at a year 11 level, I'm willing to answer them for you or research them for you. Ask anything of me, if I don't know it I can ask my teacher or another teacher here at the academy.

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Q:

(these notes are the ones i get from my teacher at school. Mrs Ambroselli)

SI units are the units used internationall

Derived units- Quantities from the basic quantities

Scientific notation

-Used for very very big & small numbers

-Written as factors of 10

-Numbers written in scientific notation re made up of 4 parts

-The mantissa is always above one but below 10

-if the power is negative (-ve) - a small number

-if the power is positive (+ve) - a big number

Significant digits

-used for accuracy

-Non zero digits are always significant (1,2,3.....etc)

-All final zero after the deicmal point are significant eg. 56.0 has 3 significant digits

Operations using significant digits

-Sum or difference of two values is as precise as the least precise values

Percentage uncertainty = Absolute uncertainty/ob

Uncertainty calculations

for +/- add absolute uncertainty

for x\ / add % uncertainty

Error

-Error is a measure of innaccuracy

-closeness to the acepted value

Absolute Error (Ea) = 1 observed value - accepted value

Relative Error (Er) = Ea/accepted error x 100

Acceleration

A = Vf - Vi / Tf - Ti

Where A=acceleration in ms-1 or m/s2 or m/s/s

Vf = final velocity in m/s

Vi = Initial (starting) velocity in m/s

Tf = Final time in seconds

Ti = Initial time in seconds

A= v/t

(Acceleration = velocity/time)

+ve A is accelration

-ve A is decceleration

Vf = Vi+at

Displacement using Uniform Acceleration

-Average velocity of a uniformly accelerating object is the middle velocity

velocity Time graphs

-Straight line sloping upwards indicates constant acceleration

-Straight line sloping down indicates deceleration or negative acceleration

-A horizontal line indicates zero acceleration ie constant velocity

-Displacement can be calculated by finding the area under the line

The gradient of the line gives acceleration

Equations of Motion

1. motion with (uniform) velocity

v=constant

v=s/t

or

s=vt

2. Motion with uniform acceleration

a) A=constant

b) V=v+u/t

c) V=u+at

d) s= ut+1/2at^2

e) v= u^2+2as

f) s= (u+v)t/2

Acceleration due to gravity

-Objects in a vaccum fall at the same rate regardless of their rate

-Motion due can take two forms: vertical and projectile

-galleo proved that: two objects of different masses dropped form the same hieght at the same time should strike the ground simeontaneousl

Types of freefall motion:

1. Objects being dropped or thrown down

2. Object is being thrown upwards

* upward motion is true

A gravity = -10ms^-2

Gravity= 9.8m/s

-This means an object will increase it's velocity by 10m/s in every second

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