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Question wording, please confirm

  • #1
bascially, i'm 100% sure i understod the wording of the question, below, can you please check though i confirm i interpretted right, thnx buddies

Homework Statement



the kinetic energy, E joules, of an object moving with a speed v m/s, is directly proportional to v^2.

the kinetic energy of the object is 15 480 joules when its speed is 6 m/s.

a) find a formula for E in terms of v

Homework Equations



none

The Attempt at a Solution



Ev (proportional sign) v^2
Ev = kv^2
15480 x 6 = k x 6^2
92 880 = k x 36
k = 2580

Ev = 2580 x v^2
E = 2580v




thnx for the help
 

Answers and Replies

  • #2
Hootenanny
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I am curious as to how you came to this conclusion;
Ev (proportional sign) v^2
 
  • #3
that where i get confused, i kinda thought the question meant that the kin energy times the speed is proportional to the speed squared

either that or i'm totally confused

please help

thnx
 
  • #4
Hootenanny
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that where i get confused, i kinda thought the question meant that the kin energy times the speed is proportional to the speed squared

either that or i'm totally confused

please help

thnx
No, not quite. The statement means simply that [itex]E\propto v^2[/itex].
 
Last edited:
  • #5
o rite, i see, thnx for clearing that up, but isn't it E proptional to v squared?

thnx buddy
 
  • #6
Gokul43201
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The trick (if I understand the source of your confusion) is to learn to partition the sentence correctly.
the kinetic energy, E joules, of an object moving with a speed v m/s, is directly proportional to v^2.
Try to throw away all non-essential details and extract the thrust of the statement, i.e., some property of some object is proportional to some other property.

Then you can keep track of the details separately...
Some property = KE
some object = "object moving with a speed v"
some other property = v^2

The upshot of this is that one property is proportional to another, namely, KE prop v^2

Perhaps it would help if you read the sentence as though it were written this way: the kinetic energy, E joules, (of an object moving with a speed v m/s) is directly proportional to v^2.
 
  • #7
Hootenanny
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o rite, i see, thnx for clearing that up, but isn't it E proptional to v squared?

thnx buddy
Sorry, that was a typo. Now corrected :smile:
 
  • #8
The trick (if I understand the source of your confusion) is to learn to partition the sentence correctly.
Try to throw away all non-essential details and extract the thrust of the statement, i.e., some property of some object is proportional to some other property.

Then you can keep track of the details separately...
Some property = KE
some object = "object moving with a speed v"
some other property = v^2

The upshot of this is that one property is proportional to another, namely, KE prop v^2

Perhaps it would help if you read the sentence as though it were written this way: the kinetic energy, E joules, (of an object moving with a speed v m/s) is directly proportional to v^2.

o rite eyh that'll be where i was going wrong lol, thnx for that, i understadn now :D
 

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