- YumYum247

elp me please!!!!!

- jamiebookeater

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- YumYum247

|dw:1441153687515:dw|

- YumYum247

@IrishBoy123 Police help me!!! :)

- YumYum247

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## More answers

- YumYum247

@dan815 Dan my love come rescue me from this terrible nightmare HUN!!!! :"D

- YumYum247

Any idea?????????????????//

- dan815

not sure, the question is a little too vague for me

- dan815

does it mean launched by compression of spring or was it just thrown up from equilibriium position

- dan815

the spring i take it is not attached to the ground

- YumYum247

don't worry about the compression or anything, just work with the given variables...

- dan815

im trying to determine what is given

- YumYum247

the g = -9.81m/sec^2, Vi = 2.3m/sec, angle = 78deg

- dan815

thats just a projectile problem it has nothing to with spring

- YumYum247

but we have to solve the problem in projectile sense of view....i think.

- dan815

oh theres nothing to that then just find V_y

- dan815

Vy= sin78* 2.3 m/s
a_y= -9.8m/s^2
h=? solve

- dan815

|dw:1441158571844:dw|

- YumYum247

and solve for what????

- dan815

height, make sure u understand what is going on

- dan815

it should be natural once u understand what is going on

- dan815

you have an inital velocity, and ur acceleration is tellng u how much of that velocity u are losing per second

- dan815

when the object is at its peak height, its veloicty is 0, so we want to see the time it has been travelling under that acceleration for

- YumYum247

ok but i can't see the picture you just posted properly, some of the content is blocked/missing..... :(

- dan815

once u get the time its been travelling, you can solve for the actualy distance it travelled in that time

- dan815

zoom out to see everything

- dan815

http://prntscr.com/8bltc5

- YumYum247

ok...bit one more thing, there is a formula for this but i'm sure if that would work...let me post it...hold up :)

- YumYum247

H=u2sin2(Î¸)2g

- YumYum247

it looks something like this, le me draw.

- YumYum247

|dw:1441159093595:dw|

- YumYum247

is this right???????????

- dan815

im thinking that is from equating the kinetic and potential energy together

- dan815

see if both ways gives the same answer if it does then its right

- YumYum247

but what if it doesn't???:O

- dan815

1/2 m * V_Y^2 = mgh
therefore
V*sin ^2 (78)/2g = h

- dan815

i think you are relying on formulas too much, you have to really understand physics or it wont work

- YumYum247

ok what to do for now???? which one tho????

- dan815

check both

- YumYum247

aight.....!!! Thanks!!! :"D

- dan815

i know whats gonna happen both ways, but i want you to explore

- YumYum247

ok dear, i'll try to explore. Thank!!

- YumYum247

what is the formula for projectile motion, i didn't get it for a sec.... t = Vf +Vi + 1/2(G+t^2)

- YumYum247

- dan815

|dw:1441161107807:dw|

- dan815

|dw:1441161320080:dw|

- dan815

u can do this integral too to see if gives u the same distance

- dan815

http://www.wolframalpha.com/input/?i=t%3D2.3sin%2878%29%2F%289.8%29%2Ch%3D2.3sin%2878%29+*+t%2B1%2F2%28-9.8%29*t^2

- YumYum247

nooooooooooooooooooooooooooooooooooooooi 2 is not the power.....

- dan815

http://www.wolframalpha.com/input/?i=h%3D2.3^2*sin^2%2878%29%2F%282*9.8%29

- YumYum247

2 multiplies with the sign...i have the formula sheet with me rn.

- dan815

both ways same answer

- dan815

the formula is wrong

- dan815

i showed u how the formula is derived

- dan815

it comes from kinetic1+potenrial1= kinetic2+ potential2

- YumYum247

ok......

- dan815

so in the beginning theres only kinetic as the height is 0
and in the end theres only potential as the velocity in y direction is 0

- dan815

1/2mv^2=mgh
m cancel both sides
1/2 V^2=gh
so
h=1/2v^2/g

- YumYum247

yah makes sense......

- dan815

or h=v^2/2g

- dan815

now v^2 is the V_y^2so

- YumYum247

wait what do you mean by Vy tho...vertical velocity O_o

- dan815

V_y^2=(Vi*sin 78)^2 =Vi^2 * sin^2 (78)

- dan815

yes Vy is the vertical velocity

- dan815

Vi is more like the speed or the veloicty in that specific direction

- YumYum247

ok thanks a lot.....i mean alot. :)

- dan815

okay but u better understand this stuff

- dan815

the most important thing is you are able to visualize and work through it in your head

- dan815

or paper

- YumYum247

yah i'm doing it....it takes time bro, gimme sumtime bro.......

- YumYum247

|dw:1441162910616:dw|

- YumYum247

@dan815 i'm stuck!!!! :"(

- dan815

what kinda equation is that

- dan815

its h(t) = 0 + v_y*t+1/2 * a*t^2

- dan815

h(t) is notation for h as a function of t

- dan815

Vy= vi*sin (78)
t=Vy/9.8
h = 0 + v_y*t+1/2 * a*t^2

- YumYum247

i didn't post the whole thing but i followed your steps.....

- YumYum247

Vy= vi*sin (78)
t=Vy/9.8
h = 0 + v_y*t+1/2 * a*t^2
if you simplify this you get something i posted.....

- dan815

\[V_y= vi*sin (78)\\ t=V_y/9.8 \\ h= 0 + v_y*t+1/2 * a*t^2\]

- YumYum247

that's a quadratics expression.

- YumYum247

if you rearrange it.

- dan815

its not a quadratic u know what t is already u plug that in

- YumYum247

omg...i didn't see that....sory....:) let me try again....

- dan815

Vi=2.3
Vy=2.3*sin(78)
t=Vy/9.8
h=0+Vy*t + 1/2 a*t^2

- YumYum247

don't say anything just let me take a look at this with my eyes and brain open...

- YumYum247

i got it....

- YumYum247

Thanks!!!

- dan815

check with
h=Vy^2/(2g)

- YumYum247

yah that works for me....

- YumYum247

h = vertical velocity/2g gives me the right answer....

- YumYum247

Anyways don't stress yourself..... go watch a porn to cool off a lil.... :"D
i'll get this done on my own now!! :)

- YumYum247

btw the example you gave me on wolframe didn't have the time input for T.

- YumYum247

|dw:1441164804108:dw|

- YumYum247

@dan815 please take a look at this.

- YumYum247

i have to use quadratics formula here....

- dan815

- YumYum247

yes i get that...but what happened at the very last step....

- YumYum247

idk if the website used quadratics formula, or what to get the answe!!!

- YumYum247

im stuck at the very last part....

- YumYum247

|dw:1441165539159:dw|

- YumYum247

never mind i got it....

- YumYum247

Thanks !!

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