U probably know ur symbol of units…. right?
You should know ur symbol of units
In addition, with prefixes, u r given them in the data booklet
Idk, I’ll look at page 1
I gatchu
Do u know how to check equations?
This is my run through:
e.g. P = ρgh
1. Find the original symbols stated in these symbols
2. And then see if they equal each other
3. This is definitely hard and unfortunately, decent marks for these man D:
Describe scalar quantity?
Only magnitude e.g. temperature = 20°c
Describe vector quantity?
Magnitude and direction e.g. velocity = 50 m/s East
Incase, u can look at page 6 for common vectors/scalars but, how do u find resultant vector of a polygon of vectors?
Tell me all about combining vectors
A+B+C+D =E
If you know, you know
Parallel & anti-parallel vectors
- So A & B are moving towards the same direction
- It appears A has a bigger force than B
- Together combined = resultant vector (A + B)
- Another rendition:
- C going forward, D going backwards towards C
- Resultant vector = C - D
Non-parallel vectors
- The head-to-tail method
- Parallelogram of vectors:
If A and B form two sides of a complete parallelogram, C = resultant vectors between the opposite corners
So it seems like them right angle graphs but it’s parallelogram….
(if u know u know)
Just know that in-between them, is the resultant vector ONLY IF THEY FORM A PARALLELOGRAM
- Polygon of vectors:
Lets say u have a “5 sided shape” in terms of vectors ofc
If we aren’t given the vector for the last side (anti-clockwise), you add the remaining vectors all together to gain the resultant vector
A + B + C + D = E
How do u actually resolve vectors?
It appears to be Soh Cah Toa
- Gain the resultant force through those equations
- Then always get the angle by also using those equations
How does getting the horizontal & vertical component work?
- It’s always them xy typa graphs (if u know u know
- With the force (N) always being the “hypotenuse”
- Technically u r always using the force to gain the horizontal/vertical component
(so u can re-arrange for the other stuff ,’:) - Be aware with how it says cos/sin tho, like that just means it always has to be in that form yano?
What’s the equation for horizontal component?
x = Z cos θ
Z = the resultant vector
remember it’s horizontal so ofc it’s the angle that’s…. horizontal
or maybe that’s the only angle lol
What’s the equation for vertical component?
y = Z sin θ
Z = the resultant vector
remember it’s vertical so ofc it’s the angle that’s… vertical
or maybe that’s the only angle lol
How do u do resolving several coplanar vectors?
(know this is the applied questions part type shi)
- Resolve horizontal & vertical components for each force
- Ye so u use that equation - Add up horizontal and vertical components separately
- Basically, u’d be given the force sometimes but u still need to do the equation and there that’s how where u add them up (to gain the full horizontal/vertical component)
- Additionally, sometimes it’ll be in the opposite direction, therefore you do minus cuz…. yeah (parallel & anti-parallel vectors) - Calculate the resultant force using Pythagoras theorem
- So u have your horizontal & vertical components, a²+b² = c² <– resultant force
- Turn it into a triangle to make it easer - Find angle using trigonometry
- Soh Cah Toa
- Make a triangle so it’s easier too (too)
Btw, ALWAYS find resultant force and angle regardless of the question. Cuz sometimes it don’t even say to find it, trick question type shi
^^ he’s right u know
Not a good idea, I’m gonna make notes for all but only the “imp” stuff, not ideal but it’s cuz it’s literally tmrw so, yea fuck.
IT’S NOT TOOOO LATEEEE
Lock in
Okay
Tell me about objects on a banked slope
- U r usually given like the “main triangle” that the person is sliding down on
- But then, u have to kind of create “another triangle” for the person sliding:
- The contact force being perpendicular to the right angle (vertically up, the arrow is up)
- The hypotenuse on the “other triangle” is w=mg
- From the main triangle, that’s the component of weight down the slope
- U can gain the angle above the right angle from the “main triangle” (if u know u know) - Then u can just use trigonometry like normal to find the unknown forces (at first, i thought it was some opposite of horizontal/vertical components. Oh boy was I wrong….):
- Contact force in this case would be = Cah
- Component of weight down the slope = Soh - Wow that’s pretty simple! But be aware of finding frictional force (constant speed = same force of component of weight down the slope)
Honestly, it’s better if u do a bunch of questions (btw i don’t even do a bunch of question ¬.¬)
Equation for density? (ρ)
And additional stuff?
ρ = m/v
ρ = density
m = mass (kg)
v = volume (anything3
- There’s possibilities it’ll ask us for values from the volume, therefore a lotta re-arranging
- In addition, it can be any volume (sphere, cuboid, cylinder, etc.)
Define the centre of mass
The point where total mass of an object can be treated as a single point
Define the centre of gravity
Single point within a body at which the entire weight of body may be considered to act
Condition for CoM & CoG to coincide
When there is a uniform gravity present in the region
How to find centre of gravity of an object?
Can’t say steps, not enough time
- Plumbline, hang, draw line, lines meet, WOW
- Hang object freely from 1 corner
- Draw line from suspended plumb line you’ve hung
- Hang object freely from another corner
- Repeat step 2
- Where line meets = CoG
What causes a vehicle to tip over?
- When it’s centre of gravity passes the point of pivot
- However sometimes it will topple faster based on CoM
How do you increase size of moment?
(2 ways)
- Increase force
- Increase perpendicular distance between force and pivot
Unit of moment?
Nm
State the principle of moments
In a rotational equilibrium, ∑ clockwise moments = ∑ anti-clockwise moments about the same point
obviously say all in words tho.
2 conditions for a system to be in equilibrium?
- No net force
- No net moment
Define moment of a force?
The turning effect of a force applied to a rotational system at a distance from the axis of rotation
There’s not enough time…. all i can say is that, be aware of this one question that’s def gonna be there and you should know that it’ll be the most complex
Additionally, be aware of suvat questions incase there might actually be one tbh
Eventually, I’m gonna do some questions on this topic, one of the questions just can’t wrap my head around (it’s the complex one)
Yes boss
¬.¬
