Vectors.....?

Question

what are the answers for these and the solutions:

diane rows a boat at 8.0 m/s directly across a river that flows at 6.0 m/s

a. what is the resultant speed of the boat?

b. if the stream is 240 m wide, how long will it take diane to row across?

c. how far downstream will diane be?

pls help.. thanks.

Answer 1

a. using pythagoras theorem,

speed = sqrt (8^2 + 6^2)

speed = 10m/s

b. time taken = 240/8=30s

c. distance = 30*6= 180m

Answer 2

dear me, if you are taught what a vector is, you can figure out the resultant speed of 8 across and 6 down.

a) Remeber pythagoras?  sqrt(8^2 + 6^2)m

Some futhrter hints:

if the journey takes t  seconds,

b) she crosses at a speed of 8 so 8*t = 240

c) and she moves downstream  6*t

That wasn't hard was it??