elizabethy
I'm the best !!
hi ppl
how r u guys finding this ???? easy or hard????
how r u guys finding this ???? easy or hard????
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Projectile Motion!! (2 Viewers)
- Thread starter elizabethy
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professor
Member
easy, esp with physics background
CHUDYMASTER
Master of Chudy 'n' Curry
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Hmm yes if you don't do physics it can be hard to understand.
My suggestion is that you read all the derivations and all the stuff in the book. Most of the questions are regurgitations of those examples which are provided in the books.
Just remember that your foundations are : y(doubledot)= vertical acceleration = gravity = -10 (or -9.8) m/s^2 and x(doubledot) = horizontal acceleration but since horizontal VELOCITY is always constant in the case of throwing a projectile (in favourable conditions, like a vacuum), the x accleration = 0.
From knowing those 2 starting values, you keep integrating to find range/velocity (x) and height/velocity (y). You'll be given values to find the constants, don't forget those constants in integrating!
Be mindful that you sometimes need to know simple facts to work out certain values, like when you have a maximum height (since it is a parabola), the vertical component (ydot) = 0.
Also think about a situation practically to solve those one line questions like "What angle would you throw the ball at to attain max range?" Sometimes you'll need to show this mathematically, in which case you'll generally use the sine ratio to show that the angle would have to be 45. (again, this can be shown through derivation/use of a formula, R = v^2sin2theta/g where R is the range, g is gravity and v is the projected resultant velocity)
Anyway, point being, you need to practise and repeat a lot if you're not a physics person.
Hope it helps.
My suggestion is that you read all the derivations and all the stuff in the book. Most of the questions are regurgitations of those examples which are provided in the books.
Just remember that your foundations are : y(doubledot)= vertical acceleration = gravity = -10 (or -9.8) m/s^2 and x(doubledot) = horizontal acceleration but since horizontal VELOCITY is always constant in the case of throwing a projectile (in favourable conditions, like a vacuum), the x accleration = 0.
From knowing those 2 starting values, you keep integrating to find range/velocity (x) and height/velocity (y). You'll be given values to find the constants, don't forget those constants in integrating!
Be mindful that you sometimes need to know simple facts to work out certain values, like when you have a maximum height (since it is a parabola), the vertical component (ydot) = 0.
Also think about a situation practically to solve those one line questions like "What angle would you throw the ball at to attain max range?" Sometimes you'll need to show this mathematically, in which case you'll generally use the sine ratio to show that the angle would have to be 45. (again, this can be shown through derivation/use of a formula, R = v^2sin2theta/g where R is the range, g is gravity and v is the projected resultant velocity)
Anyway, point being, you need to practise and repeat a lot if you're not a physics person.
Hope it helps.
Last edited:
m3h_m3h
Member
projectile motion is pretty straight forward. i find simple harmonic motion alot more difficult.
elizabethy
I'm the best !!
nah i think SHM is better but projectile isn't bad either!!!
underthesun
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motion is generally easy, binomial is hard tho
further related rates are pretty hard too, got some pretty annoying questions that i'll post soon..
further related rates are pretty hard too, got some pretty annoying questions that i'll post soon..
M-THIS
Member
do you suggest me (not a physics person) to read a physics text book?
is it heaps more complicated? would it get me more confuseD?
if so what book? any suggestions pls
is it heaps more complicated? would it get me more confuseD?
if so what book? any suggestions pls
CHUDYMASTER
Master of Chudy 'n' Curry
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Nah, just look some of the basics up on the net.
Understand the fundamentals - that horizontal motion is always non-accelerated and vertical motion is accelerated by gravity. When a projectile goes up, it goes against gravity, making acceleration negative. This is all assuming it's a vaccuous situation.
Understand the fundamentals - that horizontal motion is always non-accelerated and vertical motion is accelerated by gravity. When a projectile goes up, it goes against gravity, making acceleration negative. This is all assuming it's a vaccuous situation.
freakofcool
Member
with a physics background it's definately easier... i just have to make sense of some q's! they're always so wordy...!
Mathematician
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This should help for ppl needing help in the concepts
To solve Projectile questions u must understand a few concepts.
(1)The velocity throughout the trajectory(the path taken by the projectile which is parabolic) is constantly changing. This trajecotry velocity has Vertical and Horizontal components and the vector sum of these independent components is the trajectory's velocity.
(2) There is only one force acting on a projectile when it is in the air and this force is gravity.
(3)Gravity acts in the vertical direction and therefore there is a acceleration in the vertical direction since forces produce accelerations.
(4) All throughout the Projectile the Horizontal Velocity is constant since there is no force to produce an acceleration in the horizontal direction.
(5) When u throw a ball in the air just before it comes down from up , u notice a stop before the turning point, During this stop the velocity is 0 and it has obviously achieved its maximum height.
Therefore at maximum height the velocity is at rest or 0.
(6) the time T is the same time for the vertical and horizontal components since both are normally talking about the time taken in the air.
(7)when they ask what is the velocity when the object strikes the floor they are not talking about the vertical or horizontal velocitys they are talking about the trajectory's velocity which is the vector sum of the two components and this velcocity is not 0 because they mean the velocity just before it makes contact.
All this should make u a master in projectile motion if u know the math.
To solve Projectile questions u must understand a few concepts.
(1)The velocity throughout the trajectory(the path taken by the projectile which is parabolic) is constantly changing. This trajecotry velocity has Vertical and Horizontal components and the vector sum of these independent components is the trajectory's velocity.
(2) There is only one force acting on a projectile when it is in the air and this force is gravity.
(3)Gravity acts in the vertical direction and therefore there is a acceleration in the vertical direction since forces produce accelerations.
(4) All throughout the Projectile the Horizontal Velocity is constant since there is no force to produce an acceleration in the horizontal direction.
(5) When u throw a ball in the air just before it comes down from up , u notice a stop before the turning point, During this stop the velocity is 0 and it has obviously achieved its maximum height.
Therefore at maximum height the velocity is at rest or 0.
(6) the time T is the same time for the vertical and horizontal components since both are normally talking about the time taken in the air.
(7)when they ask what is the velocity when the object strikes the floor they are not talking about the vertical or horizontal velocitys they are talking about the trajectory's velocity which is the vector sum of the two components and this velcocity is not 0 because they mean the velocity just before it makes contact.
All this should make u a master in projectile motion if u know the math.
truly-in-bliss
my love is like woah!
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3u maths just does not make ani sense to meeh.....if only eveyrhting is as logical as 4u maths....
funkychickie
Member
hey ur not allowed to use the physics formulas to do any of this stuff r u? cause ppl tell me u r and others r tellin me u arent??? im confused i kinda get the stuff though.. i know it but it sometimes trips me up!!!
kini mini
Active Member
You must derive everything from the two basic equations, integrating all the way and determining constants. Using the physics formulae automates the integration and is forbidden
. Feel free to use them to check your answers if you can .
