Thread: So who's good at math? ;]

1. So who's good at math? ;]

I need help 2. The energy, E, of an object moving horizontally is directly proportional to the speed, V, of the object. When the speed is 10 m/s the energy is 40000 Joules.
Part A: Find an equation connecting E and V.
Can anyone at least give me a hint please?  2. e 4,000 joules per v 1m/s 3. Duke    Join Date
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1,970  Originally Posted by SIGMA [1s1k] e 4,000 joules per v 1m/s

that is the right answer, and it took me barely 20 seconds to get to it 4.  Originally Posted by Darrenb209 that is the right answer, and it took me barely 20 seconds to get to it
I needed to find it in a direct proportion equation like this:

x=ky

k=constant btw :L

I worked out what type of formula I just dunno what it is
Last edited by RMH94; 09-30-2010 at 01:23 PM. 5. Wow, i just glazed over reading that post.... Ill duck lower so it can over over my head quicker next time ! 6. Earl        Join Date
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436  Originally Posted by RMH94 Can anyone at least give me a hint please? Energy (kJ) = Speed (ms) x 4

i.e k=4

you can convert to SI, as i cba, and im not doing it all for you 7. 2. The energy, E, of an object moving horizontally is directly proportional to the speed, V, of the object. When the speed is 10 m/s the energy is 40000 Joules.
Part A: Find an equation connecting E and V.
I know an equation that requires the knowing the distance travelled. I will assume the object moved at 10m/s for 10 seconds. thus it moves 100m.

newtons x m = joules
400newtons x 100m = 40,000 joules

400 newtons of horizontal force moving 100m = 40,000 joules of energy
40,000 joules / 10s = 4,000 watts of power output
Last edited by Rota; 09-30-2010 at 04:44 PM. 8. I'm not very good at math but does that mean the equation is 400N x V = 4,000E? 9.  Originally Posted by Richie_B I'm not very good at math but does that mean the equation is 400N x V = 4,000E?
Almost, the equation is...
N x D = E

N = newtons
D = distance in meters
E = joules

edit: I found a velocity equation

v^2 = 2E / mass
so...
10 m/s squared = 2(40,000 joules) / 800 kilograms
Last edited by Rota; 09-30-2010 at 05:16 PM. 10. Rota is correct.

Just kidding. I don't even understand the question.  Posting Permissions

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