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Wind Power B/C

Posted: July 30th, 2015, 12:59 pm
by samlan16
This question marathon is for the 2015-16 event Wind Power, which involves a written portion about energy.

First question (I'll keep this simple): Suppose that you are shooting an arrow of mass 21 g from a height of 1.5 m at the bottom of a hill 9.42 meters tall. If you fire the arrow and it lands on top of the hill,

a) How much gravitational potential energy did the arrow gain?
b) What was the initial velocity of the arrow?

Re: Wind Power B/C

Posted: July 30th, 2015, 4:19 pm
by liberalartslover
a) 1.63 J
b) 12.5 m/s

Re: Wind Power B/C

Posted: July 30th, 2015, 5:55 pm
by samlan16
liberalartslover wrote:
a) 1.63 J
b) 12.5 m/s
A is wrong. I'll let you figure out why.

Re: Wind Power B/C

Posted: August 15th, 2015, 2:59 pm
by liberalartslover
Really how?
(9.42-1.5)*9.8*.021 = 1.63

Also if part B is 12.5 then part A has to be 1.63 because of conservation of energy.

Re: Wind Power B/C

Posted: August 15th, 2015, 3:36 pm
by samlan16
liberalartslover wrote:Really how?
(9.42-1.5)*9.8*.021 = 1.63

Also if part B is 12.5 then part A has to be 1.63 because of conservation of energy.
Sig figs.

Re: Wind Power B/C

Posted: August 15th, 2015, 4:29 pm
by liberalartslover
*sigh*

1.6 and 13 then?

Re: Wind Power B/C

Posted: August 15th, 2015, 6:47 pm
by samlan16
Correct.