Mistakes Flashcards
When using ideal voltmeter and trying to find out etc what should you do
Find out currents first, don’t fall into trap that ideal so takes all voltage, what you should do is think ideal so no current, so it’s possible to find current, now find out voltages of others etc, need to use this approach
Ideas about gpe and ke and resistive forces
Remember ideally ALL THE ENERGY will be constant in a system, so total GPE AND KE at the top should equal total GPE AND KE at the end, but in reality loses by resistance, this what need to remember
This way can find how much lost if done total
Gravitational potential energy , where do you use height m frim?
FROM THE CENTRE OF MASS, ofc, as all mass concentrated there!
Sugar equations, the time when something thrown returns to this height can be found by
1) either finding quadratic for t
2) or easier is assuming the velocity is - when it was going upwards, due to conservation of energy
- can make a much easier us at equation
Graph transformations
Just make sure you use the minimum point to locate the graph in completed square form, then use coefficients to give positive or negative x graph
Remember that gradient of the v t graph is?
How to do that question Bakst analysing graph?
Graph proportional where grad is 5
So find equations for all see if promotional then see if gradient = 5!
How much distance does a particle on a wave actually travel?
It don’t travel anywhere, only up or down, so in one wave, 4 x A
Find out how many waves have happened, multiplied by 4a
On a pulley what are forces acting on it?
The force holding it up
And two tension forces going down in Esther side!! Thus the force holding up is two times the tension ti stop it from accelerating downwards!
This is the force in the coupking
FORMULA FOR EXTERNAL ANGLE!
Is 360/n not internal!
Remember newton third law key part (ending)
That the forces are OF EQUAL TYPE! So to check make sure they are
For finding distinct trots to some long equation what to do?
Remember root just solutions, so if equal to something it’s just solutions to that, no need to rearrange for 0 etc
Just say if y= k wheee will I get 4 intersections , between these two points, find them and go on.
What is definition of increasing function?
When derivative is GREATER THAN KR EQUAL TO 0!
Remember if graph not straight for v t for throwing up what does this show
That there is air resistance, thus energies are lost!
BIG MISTAKE
How to compare surfs?
Make sure to convert to surf form first, then you can easily compare them!
Remember log rules
If you add you multiply add if you subtract you divide etc
Remember cables in a cable still follow parallel resistance rule
So using resitivity etc equations it becomes parallel
On a semi circle how are energy changes happening
At the point the difference in gpe = difference in height should a converted to ke, but since still it converted to friction to this much energy lost to friction
Now to find force divide by distance and multiply by other distance
This is a single fraction
Now to find ke all the gpe should a converted to ke but there is force too, so do meh - friction and you get answer
Average power equation?
Force x average velocity
Remember to find potential difference it’s potential at top - bottom
To find potential at top or bottom do how much is used and subtract that from emf
MAKE SURE DIRECTION IN MOMENTUM IS CORRECT
Remember if two bit they gonna be opposite directions, always easier for those to just do Ft= Mv + MU
WITH TWO MAGNETS, WHAT IS THE MAGNETIC FIRCE BETWEEN 5EM?
The same assuming constant magnetic field!
WHATS THE ONLY THING THAT CAN AFFECT MASS NUMBER DECAY
Alpha so look at this first
The rest that effect the mass is beta - which a neutron becomes a proton so it increase
USE ENERGY IDEAS WHATEVER SUSTEM WHY?
not guaranteed the acceleration is constant throughout time so can’t use
Remember the distance L in f = bil is
The length of wire in the MAGENTIC FIELD
VELOCITY EQUATUON (BASICS)
change in velocity / CHANGE IN TIME
