a simple physics problem..

[kmart64]

for some reason, I can't get the right answer...its pretty easy.

Just look at particle (c)



v initial is 10 m/s at t=0 s. What is the velocity at t=6 sec?

If you could provide an explanation, that would be nice. Thanks

[xwade01]

Wouldn't that be 60m/s??

[kmart64]

for some reason, no

[owequitit]

Is it 70m/s?

Any other info they gave you would be helpful.

Are you working with vectors?

[ehulst]

v initial = vfin + at

vfin= V Final
A= Graviational Acceleration
T= Time

[kmart64]

god, my damn messed up calculation...the answer is 90 m/s...

[Accord R33]

v initial = vfin + at

vfin= V Final
A= Graviational Acceleration
T= Time

this would work, assuming you knew the exact acceleration at t=6. from the graph you could say its -10

[aero]

OK... I got it.. lemme type up an explanation

[aero]

If you look at the graph, its giving you the acceleration... How much it is increasing per second.

your initial velocity is 10 m/s.

Now look at the graph from the first point to the change of slope. You went from 0-2 seconds, and the acceleration went from 10m/s/s(squared) to 30m/s/s. So the average acceleration over that period of time is 20m/s/s. So 2 seconds at an avg. acceleration of 20 gives you 40m/s faster than you started (50m/s).

For the next two points, you do the same thing. You also get an average of 20m/s/s. Which adds another 40m/s of velocity. Add that to the 50m/s you started with, giving you 90m/s. The final two seconds will give you an average acceleration of 0m/s/s, so the velocity does not change.

You could also just average the whole last 4 seconds, but 2 seconds at a time was easier to explain.

[PakaloloHonda]

OK... I got it.. lemme type up an explanation

K .. I'm lost .. why does it appear to start out at -30 ?
brb .. I gotta get another glass of champagne .. hic-up .. err, scuse me ..

A Hui Hou !!!
Tomi

[aero]

K .. I'm lost .. why does it appear to start out at -30 ?
brb .. I gotta get another glass of champagne .. hic-up .. err, scuse me ..

A Hui Hou !!!
Tomi

Champagne wont help

You gotta read from left to right meng. They all start out at 10.

a. is position
b. is velocity
c. is acceleration

edit: if you need it more explained lemme know.... not you tomi

[kmart64]

nah, i got it...there is a simple way to do it. Since all u can do is look at the graph, you just find the displacement (area) from time 0 to time 6. since 5 to 6 is a negative number, you add it to the number you find from 0 to 5. Then since the initial condition says that at t=0, the initial velocity is 10, then the answer will be 90. Thanks for ur guys help though. I was dumb and made bad calc errors.

[kmart64]

oh yea aero, you would be right, but in this problem it is asking for instantaneous velocity. I think thats what ur saying?

[PakaloloHonda]

edit: if you need it more explained lemme know.... not you tomi

Tomi <~~~ movin to the back a the class .. hic-up ..

I meant 10 .. I was lookin at the wrong .. errr, I waass .. uhh, nebbermind ..

Thud !!!
Tomi

[aero]

nah, i got it...there is a simple way to do it. Since all u can do is look at the graph, you just find the displacement (area) from time 0 to time 6. since 5 to 6 is a negative number, you add it to the number you find from 0 to 5. Then since the initial condition says that at t=0, the initial velocity is 10, then the answer will be 90. Thanks for ur guys help though. I was dumb and made bad calc errors.

Yeah, you can also do it that way... taking the area under the curve.