The trial exams that have extremely hard, incorrectly worded questions...

[xZero]

Notice the startup voltage on the diodes, it requies 1 voltage just to connect the circuit, hence it will only have 14v running in the circuit.

[FromBaghdadWithLove]

uhh whats wrong with what i did to solve this?

[onur369]

it says horizontal flight

rmax= UXxTflight  find ux=140cos40 = 107

1600/107 = 14.9

[xZero]

how did you get tflight = (2*90)/10?

[yawho]

some situations in questions are too unrealistic, open to different interpretations and undoable

[FromBaghdadWithLove]

@xzero, tflight = uy (verticle component of vel = 90) x2 /gravity (10) which = 18s

[FromBaghdadWithLove]

@yawho, can u please rephrase that in the answer format...? im correct with my answer right, and they are wrong.

[yawho]

sorry, my comment referred to the thread, not your post

[davidle_10]

I think you are right, because time is dependent on the vertical motion. Badly calculated question, because if t were to equal 14.9 seconds then the overall speed or the angle would not be the same as given.
At max height
t=14.9/2=7.45s 
u=u+at=0+10x7.45=74. 
u/v=sin(x) x=sin^-1(74.5/140)= 32.15 degrees
or
74.5/v=sin40 v=74.5/sin40=115.9

[onur369]

It clearly says horizontal flight....
As horizontal distance is given, 1600m.

You can just use Rmax = ux x tflight
find ux by: ux=ucosangle    140xcos40 = 107.2
rearrange :
tflight = rmax/ux
=1600/107
=14.9

[xZero]

the solution given is definitely correct, this is a real life scenario, there's gonna be air resistance and all that sort of stuff. The fact that it doesn't say ignore all resistance and gives you a horizontal distance suggests that this isn't a perfect projectile motion. Hence you have to do what onur369 did.

Just remember, those constant acceleration equations are awesome until it meets air resistance

[dopplereffect]

Insert gay electronics question from Lisachem 2011 paper here.

[cranberry]

reckon we need to know this weird stuff??

[yawho]

good electronics questions
at 9v, the top diode is in reverse bias and goes off, the bottom diode is forward biased and stays on.
at 0v, the top diode is forward biased and stays on, the bottom diode has 0v across it and goes off.

[cranberry]

is that a yes?