Page name: Forces and Motion [Logged in view] [RSS]
2008-01-05 02:07:23
Last author: Imperator
Owner: Shadowsoul
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Forces and Motion Classroom

Taught by [Shadowsoul]

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.








Physics equations

Class notes

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

SI units are the units used internationally to measure physical quantities. They are often called the metric system

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/observed measurement x 100%

Uncertainty calculations
for +/- add absolute uncertainty
for x\ / add % uncertainty

-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


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


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 simeontaneously

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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