IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: aiyla on November 17, 2009, 08:50:03 am
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A cricketer hits a ball straight up in the air, it leaves the bat at 16.8 ms-1 and has a mass of 160g .
i did part a) and b) they asked for kinetic energy & height
now part c i don't know , the question says
c) if in reality, flying up in the air and back down again is process with an efficiency 88%, the how fast will the ball be traveling when it returns to the start point ?
please could some one explain the process and how exactlly should we solve this ?
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I need to see the question and your answers to give you an answer..
I generally know that efficiency = work out/work in x 100% = (force * d)/(force * d) x 100%
In other words, ---> Actual/Ideal x100%
Don't really know how to help you, without seeing the real question.
FYI:
(http://upload.wikimedia.org/math/6/b/3/6b32175ed283e48696215a60a264ee36.png)
??? I'm confused myself. lol.
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Give me 5 mins to get to a pc
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A cricketer hits a ball straight up in the air, it leaves the bat at 16.8 ms-1 and has a mass of 160g .
i did part a) and b) they asked for kinetic energy & height
now part c i don't know , the question says
c) if in reality, flying up in the air and back down again is process with an efficiency 88%, the how fast will the ball be traveling when it returns to the start point ?
please could some one explain the process and how exactlly should we solve this ?
KE=1/2mv^2=0.08*16.8^2=22.5792
Final KE=0.88*22.5792=19.69J
1/2mv^2=19.69 so v=sqrt(19.69/(1/2*0.16))=15.76m/s
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the book Questions have no answers at the back, thats why its difficult to know if the answers are right or wrong .
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thanks alot mr.smith =D
i really appreciate it <3