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mod 5 phy prjectiles (1 Viewer)

Tryingtodowell

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
 

Average Boreduser

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
whatevr u do dont use integration. I did that in my zhangs test and I had to solve a quartic 😭 😭 😭
 

coolcat6778

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
This is literally the most basic thing. People like you are why the physics syllabus has no more math than it does.

use this with the y component. That allows you to find the time of flight. Then using this formula to find t if you cannot factorise. First you make everything equal to zero. Then using the formula sx=ut you can find the range using time of flight and x component
 

Tryingtodowell

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This is literally the most basic thing. People like you are why the physics syllabus has no more math than it does.
yeah so help me instead of berating me 😭 I know its basic and im probably gonna look back on this in a couple of days and be like 'why tf did I ask this' but rn idk
 

liamkk112

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
yes, we know that s = ut+0.5at^2 right
so in the x direction, thats
s_x = u_xt+0.5(0)t^2
or s_x = u_xt as we assume 0 acceleration in horizontal direction
now in general u_x=ucos(theta) where u is initial velocity, theta is the angle of elevation that the projectile is launched at (this is clearly seen through drawing a triangle)
that’s where the theta can come in, you just sub that into the above formula
 

Tryingtodowell

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yes, we know that s = ut+0.5at^2 right
so in the x direction, thats
s_x = u_xt+0.5(0)t^2
or s_x = u_xt as we assume 0 acceleration in horizontal direction
now in general u_x=ucos(theta) where u is initial velocity, theta is the angle of elevation that the projectile is launched at (this is clearly seen through drawing a triangle)
that’s where the theta can come in, you just sub that into the above formula
ohh 💀 ok tysm
 

igor9

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think abt it logically. the range is when Ry = 0, then find the time associated with that, and then sub that time into Rx. obviously just use the corresponding SUVAT for these.
 

coolcat6778

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whatevr u do dont use integration. I did that in my zhangs test and I had to solve a quartic 😭 😭 😭
You mean quadratic? Quartics are polynomials to the power of 4, how can you derive a quartic from a quadratic? Quadratics are literally the most easy thing to solve. If you only have 2 terms without a constant (a term thats just a number), factorise and solve using the null factor law, if you have three terms you use the quadratic formula. The stupid hsc syllabus assumes you can't solve quadratics, yet they assume you know log laws even though standard doesn't even touch logarithms let alone exponentials.
 
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moonsuyoung

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
Because projectile motion can be split into both x and y components, there are subscripts.
s_x= u_x * t
 

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You mean quadratic? Quartics are polynomials to the power of 4, how can you derive a quartic from a quadratic? Quadratics are literally the most easy thing to solve. If you only have 2 terms without a constant (a term thats just a number), factorise and solve using the null factor law, if you have three terms you use the quadratic formula. The stupid hsc syllabus assumes you can't solve quadratics, yet they assume you know log laws even though standard doesn't even touch logarithms let alone exponentials.
nah like i had two sides w one being x^2 and the other was a sqrt smn and so I had to quartic it.
 

Tryingtodowell

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
now that I done with the topic I feel so retarded for asking this 😭
 

shoulfer

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soo I recently started mod 5 physics and dont understand how you find the range
whats the formula? the y x subscripts is confusing the heck out of me coz Im used to the normal v=u+at etc etc in yr 11 😭

is there a fixed formula to find the range of a projectile? theres multiple when I search like one involving angles and one without so im confused

so yeahh thanks!
the y and x subscripts tell you with what dimension you are doing it with respect to since you take them separately for projectile motion with x being horizontal and y being vertical. Projectile motion assumes the only acceleration is due to gravity which solely acts in the vertical direction, so there is no acceleration in the x dimension (ax = 0). so with the formula s = ut + 1/2at^2, you can rewrite it to be with respect to x so sx = uxt + 1/2axt^2 where ax = 0 since there is only vertical acceleration this will leave the formula sx = uxt, then for range you have to find the total time of flight which in most cases will be when the vertical displacement = 0 so the point at which it returns to the ground, sy = uyt + 1/2ayt^2 = 0, in uyt + 1/2ayt^2 = 0 (uy = usin(θ) where θ is the angle it was projected from above the horizontal and ay = -g) leaving you with utsinθ - 1/2gt^2 = 0 then t = 2usinθ/g. you can sub that into sx = uxt to get Range = ucosθ(2usinθ/g) = u^2*(2sinθcosθ)/g = (u^2*sin(2θ))/g.
 

shoulfer

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that formula will change if the height the projectile was projected from changes and you have to derive it every time you use it anyway so there is no point in memorizing it just know where it comes from.
 

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