Conceptual Physics: Solving Problems in Math & Science

[proculation]

actually, the "d" should have been "-2", so the it should have been:

-2/-4.905=t*t
2/4.905=t²

 

[Dsoto489]

is the d (-) because it is falling?

 

[proculation]

Because you are starting from the shelf (y=0) to the ground (y=-2) and you use Vf-Vo for the difference.

 

[proculation]

So now you have "t", put it in your X equation to get the distance from the edge of the shelf where it falls. And Voila !

 

[proculation]

Physics is not that difficult you see :-)

 

[proculation]

be back in 10 minutes, corner store time for some beers.

 

[Dsoto489]

ok, now i have

X
a=0
Vo=8m/s
V=8m/s
d=?
t=.64s

y

a=9.81
Vo=0
V=6.26
d=2m
t=.64s

 

[Dsoto489]

I keep trying to plug the equation only to cancel out most of the numbers and get D=T

When and if you get back on here, could you just run me through the steps when approached with these types of problems? maybe give me another example I could run through? I really appreciate the help here-

 

[proculation]

d=Vo(or Vf it's the same) X t

remember, distance = velocity X time

 

[Dsoto489]

ok so my D=5.1 m/s/s

 

[proculation]

You run a car at 100 mph for 2 hours. How much distance will you travel ?

d = 100 x 2 = 200 miles

 

[Dsoto489]

agreed, i understand the d=v/t formula, its the bigger one, that deals with this entire problem that i keep tripping on.

 

[proculation]

d = 8 m/s X 0.64s

meters/seconds X seconds

seconds/seconds = nil

only meters stay in unit.

 

[Dsoto489]

yea, after i reread the problem i saw that i kept the s. So 5.1m is the distance the ball will end up at when i reaches the floor.

 

[proculation]

Was it so difficult ? :-)

 

[Dsoto489]

totally! ahah, ok so i have a similar problem which has the same horiz velocity of 8m/s but instead height of the table they give me time(.24s). Do i work the problem the same way?

 

[Dsoto489]

or can i just use the D=v/t

 

[proculation]

I think you have all the information you need.

Switch the variable in Y and resolve with the X equation like you did.

 

[Dsoto489]

d=8(.24)+1/2(o)(.24*.24)

 

[Dsoto489]

so the height of the table is 1.92m tall

 

[proculation]

Hummm.. as I reread your question, it would be it be if I was the teacher I would ask for the height of the table.

 

[Dsoto489]

yea the problem is looking for the height of the shelf/table

 

[proculation]

you again mixed the X and Y.

1.92m is where the ball will hit the ground from the shelf, horizontally.

 

[Dsoto489]

ok so the variables i have are

Vo=8m/s
a=0
t=.24s
d=1.92m

a=9.81m/s/s

 

[proculation]

Gimme some minutes, I will draw something.

 

[Dsoto489]

I won't be leaving anytime soon, so take all the time you need. lol thanks.

 

[proculation]

There.

 

[proculation]

See the big black line between X and Y ? That's on purpose. They are to be resolved SEPARATELY.

 

[Dsoto489]

k, i ll try out the problem, give me a sec or 2

 

[proculation]

oops there's a error. it's "a = Vf X t² + Vo"

Sorry.

I was trying to make a good drawing lol