beth12345
  • beth12345
A boy and girl both swim at 3.0m/s. They jumpinto a river 1.0km across, with a current of 2.0m/s (E). She swims straight across relative to the shore. How long (in minutes) does each take to cross the river
Physics
chestercat
  • chestercat
See more answers at brainly.com
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your free account and access expert answers to this
and thousands of other questions

anonymous
  • anonymous
You are given the velocity of boy and girl w.r.t the ground and velocity of current w.r.t ground. Velocity of girl w.r.t ground, V(g,G) = 3 m/s Velocity of current = V (c,G) = 2 m/s Now, velocity of girl w.r.t current = V(g,G) + V(c,G) [ vector sum!! ] Hope you may try to solve it now...
beth12345
  • beth12345
is it 5m per second
anonymous
  • anonymous
No... I said the vector sum, as the direction of speeds are different you can't just add both the velocities..

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

beth12345
  • beth12345
oh would I use a squared +b squared = c squared
anonymous
  • anonymous
Exactly....
beth12345
  • beth12345
i got 3.6
anonymous
  • anonymous
But, think.. For calculating time she required to cross the river if she propells herself perpendicular to the shore, would in anyway be affected by velocity of current.
anonymous
  • anonymous
Think why time depends on both components...
beth12345
  • beth12345
uhm, I don`t understand
beth12345
  • beth12345
|dw:1331693378113:dw| this is all I understand so far...
anonymous
  • anonymous
Right. See, She propells herself perpendicular to the bank at 3 m/s and at the same time she is getting pushed sideways at 2 m/s. So, her resultant velocity will be directed at an angle b/w the two.
anonymous
  • anonymous
|dw:1331693676065:dw|
anonymous
  • anonymous
Now, see 3m/s contributes to her getting across the bank. Time she requires = 1000 m / 3 m/s = 333.33 sec.
beth12345
  • beth12345
and then it makes an angle triangle like this |dw:1331693918116:dw| ?
beth12345
  • beth12345
and then it is 5.6 minutesÉ
beth12345
  • beth12345
minutes*
anonymous
  • anonymous
RIght, you may shift vectors in a plane, without changing the directions and magnitude.
anonymous
  • anonymous
Yes...
beth12345
  • beth12345
oh i think i get it, does the 2m per s affect it?
anonymous
  • anonymous
No, it doesn't effect the time, but other parameters like where she would land on the other bank does.
beth12345
  • beth12345
ok, is it the same for the boy then?
anonymous
  • anonymous
Yes, Gender doesn't effect the time as well.. lol..
beth12345
  • beth12345
oh right! haha well thanks for helping :)

Looking for something else?

Not the answer you are looking for? Search for more explanations.