Quick question

[jujimufu]

A man is swimming at 1.5m/s across a 400m river. Meanwhile, there is a current flowing at 4.0m/s to the right (as shown).
[IMG]http://img120.imageshack.us/img120/1024/physicsww2.th.png[/img]

1) How long will it take to complete the crossing?

2) In what direction would he need to head in order to arrive at the buoy (indicated by the square), which is directly across the river from the starting point?

3) If he swam directly at the buoy, and did not compensate for the flow of the river, how far down the stream from the buoy will he be?

Thanks in advance

[onlyfknhuman]

1.  use pythagorasss theorem. 

          4
       |------
1.5  |     /  x       x = sqr root [1.5^2 + 4^2]   then 400m divide by the speed u just found.
       | */
       |/
2. the angle indicated by the * but instead of North EAST ... North WEST to counter the current.

3. 
3) If he swam directly at the buoy, and did not compensate for the flow of the river, how far down the stream from the buoy will he be?


again pythagorass

  using the previous diagram replace 1.5 with 400m
replace 4 withthe answer of  [       the time found in 1, times by 4 = the horozantal distance]

then work out x is ur new distance

sorry i have my physics exam 2morow, and i totalyl forgot about motion so i hope these are right and have been helpful