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Two sprinters compete. Each accelerates at a uniform rate from a standing start. Al covers the last ¼ of the distance in 3 seconds; Bob covers the last 1/3 in 4 seconds. Who won and by how much ( the the nearest 0.001 second)?

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Two sprinters compete. Each accelerates at a uniform rate from a standing start. Al covers the last ¼ of the distance in 3 seconds; Bob covers the last 1/3 in 4 seconds. Who won and by how much ( the the nearest 0.001 second)?

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Spit out some thoughts, have you done any physics in your time?

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yeah but i forgot how to do these types, can u please help me?

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Show us what you've done so far.

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v=d/t

1/4=3x

x=1/12

1/3=4y

y=1/12

1/4=3x

x=1/12

1/3=4y

y=1/12

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That v stands for average velocity. You want an expression for constant acceleration.

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can u please set up the problem for me with an appropriate equation?

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Think of how velocity relates to acceleration.

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It might help if you looked at it in terms of differentials. Like v= dx/dt instead of x/t.

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will someone please show me at least the starting equation + work so that I may take it from there?

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Does this look familiar

[tex] x-x_0 = v_0t + \frac{1}{2} at^2 [/tex]

[tex] x-x_0 = v_0t + \frac{1}{2} at^2 [/tex]

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Cylindrical soup cans are to be manufactured to contain a given volume V. There is no waste in cutting metal for the sides of the can, but the circular endpieces will be cut from a square, with the corners wasted. Find the ratio of height to radius for the most economical can.

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Show me why/where I should help you.

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i just need help in what formula to use for that 2nd question i gave, ill do the rest

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There is no 'formula' one can just plug things into and everything will be handy dandy. Part of these word problems is to be able to figure out a formula to use that fits the problem and will help yo usolve it. If I told you the formula to use, I would be doing the hard part for you, which isnt the point.PabloPicasso said:i just need help in what formula to use for that 2nd question i gave, ill do the rest

You come up with it yourself, I'll help you if you need, but tell me what you think you need to do.

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If you have a can with radius r and height h, what would be the volume of the can? And what area A of material will it require to manufacture it? Give formulas for V and A in terms of r and h.

Now, what does "most economical" mean, in the problem statement?

How can you find the most economical can using your formulas?

Have a go at this, and post your working.

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The basic form for the volume of a cylinder is :

V = area of base * height

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