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corrine

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Jan 6, 2006
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Hey, this is the only question that I got wrong on my test and I can't figure it out, someone please help me!

"The distance that an object is from the ground is a quadratic function of length of time (t) it has fallen and the height (h) from which it falls. The is given by the formula d = ½gt² + h. If the object is 155.9 metres from the ground in three seconds and 121.6 metres in four seconds, calculate g and h.


HELP! :oops:
 
g(gravity) is a known physical constant. It is \(\displaystyle (-9.8) m/sec^{2}\)

Set up the equations and see if we get that:

\(\displaystyle \frac{1}{2}g(9)+h=155.9==>\frac{9}{2}g+h=155.9\)

\(\displaystyle \frac{1}{2}g(16)+h=121.6==>8g+h=121.6\)

Solve the system.
 
word problems

There are 60 pictures in Tom's album, including 12 taken in Boston. Is it true that 1/6 of them are from Boston? How will I me able to solve this problem?


Please and Thank-You! Bowier4
 
Bowier4 said:
Is there any limit to the number of equivalent fractions one fraction can have?
Click to expand...
Please post new questions as new threads, not as "hijacks" of other people's threads (especially utterly unrelated threads).

Thank you for your consideration.

Eliz.
 
Re: word problems

Is there any limit to the number of equivalent fractions one fraction can have? Please explain this to me.
You can multiply iy by 1/1, 2/2, 3/3,...n/n...
Is there a limit on n?



There are 60 pictures in Tom's album, including 12 taken in Boston. Is it true that 1/6 of them are from Boston? How will I me able to solve this problem?
Depends. (1/6)*60 = 10
If 12 are then 10 are, 11 are & 12 are. If they mean exactly 10 are then it is false. Your choice.

How can I find the smallest number greater than 1,000 that is divisible by 6?
Do you know that if the sum of the digits is a multiple of 3, the number is too?
Do you know that if the units digit is even it is a multiple of 2?
Do you know that if it is a multiple of both 2 and 3 then it is a multiple of 6?
Think about what you can add to 1000 so 1+x=3 and x is even.
 
Fractions

How will I estimating these fraction sums and differences?

a) 3/5+7/9

b) 10/13+3/7

c) 6/11+1/18

d) 46/50 - 4/10

e)13/16 + 5/6

f) 15/18 + 1 3/7


Please explain this to me , thank-you!
Bowier4
 
If you want to estimate them rather than solving them you cad do things like
3/5+7/9 = 6/10+7/9 is about
(6+7)/10 = 1.3
Closer
7/9=7.7/9.9
6/10+7.7/9.9 is about
(6+7.7)/10 = 1.37
The exact value is
(3*9+7*5)/45 = 1.377777...
Is that what you had in mind?
 
Re: Fractions

Bowier4 said:
How will I estimating these fraction sums and differences?

a) 3/5+7/9

b) 10/13+3/7

c) 6/11+1/18

d) 46/50 - 4/10

e)13/16 + 5/6

f) 15/18 + 1 3/7


Please explain this to me , thank-you!
Bowier4
Click to expand...

At the middle school or pre-algebra level, I think you're expected to do a quick and easy estimate. Look at each fraction and decide if it is close to 0, close to 1/2, or close to 1. Then it should be easy to estimate the answer.

For example, your first problem is
3/5 + 7/9
3/5 is close to 1/2. 7/9 is close to 1. So a quick and easy estimate of the sum would be 1/2 + 1, or 1 1/2.

In part c, you have
6/11 + 1/18
6/11 is about 1/2.
1/18 is close to 0.
So an estimate of the answer would be 1/2 + 0, or 1/2.

For part d, you have a subtraction:
46/50 - 4/10
46/50 is close to 1.
4/10 is close to 1/2.
An estimate of the answer would be 1 - 1/2, or 1/2.

An estimate shouldn't take a lot of work, and because it is an estimate, we don't expect that it must be real close to the actual answer; it should just give us a general idea of what the answer is. If we actually work out the problem, and it is WAY different from our estimate, that is a good clue that we've made a mistake.

You should (for the most part) be able to do an estimate IN YOUR HEAD. If it is much more work than that, you aren't going at the estimating process correctly.
 
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