Can someone please help me, what are the answers to these problems Ive added the link to a picture with some questions that I cant answer.

http://i38.tinypic.com/5bw8hv.jpg

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- Oct 8th 2008, 01:05 AMscienceteacherMetric Prefix Use of formulae to solve problems Please Help
Can someone please help me, what are the answers to these problems Ive added the link to a picture with some questions that I cant answer.

http://i38.tinypic.com/5bw8hv.jpg - Oct 8th 2008, 07:28 AMhjelliottQuote:

1. How far will a ball travel if a baseball thrower pitches a ball at 43 ms^-1 in 4.2s?

Quote:

2. How long would it take to produce 150 kW with 780 J of energy?

The metric Kilo prefix means 1000 times so 150 kW means 150 x 1000 watts which is 150,000 W.

If P=E/t, then that rearranged to find time would be t=E/P. The Energy we know is 780 J and the Power we found is 150,000 W. 780 J/150,000W = 0.0052 Seconds.

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3. What is the net force needed to accelerate a 5800 g, 6.2 ms^-2?

It's given that Force (Newtons) = Mass (Kg) x Acceleration (ms^-2 OR NKg^-1). We're given the mass of the objet in grams so we need to convert that to kilograms so we divide the number by 1000 giving us 5.8 kg.

The formula given F=ma is what we need so F = 5.8kg x 6.2 NKg^-1 = 35.96 N. With significant figures, that would round to 36 N.

I hope my first bit of advice on this forum was of help to you.

- Jordan - Oct 9th 2008, 03:22 AMscienceteacherHi
(Happy)Thanxx Hjelliot your a awesome guy(Happy)