A boat sails from r1=7i+6j direct to r2=5i+4j with a speed of 28.28 m/s. A second boat observes the first boats velocity as V=4(i-3j). determine the velocity and speed of the second boat
2007-01-17 05:47:16 · 3 answers · asked by Samuel_007 2 in Science & Mathematics ➔ Mathematics
r2-r1 = -2i-2j
this gives direction. note that mag here is 2.828
the vector with mag 28.28 will be -20i -20j
velocity of 2nd = -20i-20j -(4i - 12j)
= -24i-8j
this is velocity
speed = sqrt (24^2+8^2)
=8sqrt(10)
2007-01-17 06:00:37 · answer #1 · answered by Sandeep K 3 · 0⤊ 0⤋
say the second boat is going in the same direction..
then the velocity of the second boat is the difference between 28.28 and V.
if going opposite direction 28.28 + V.
going other angular direction....you will need trigonometry.
2007-01-17 06:01:04 · answer #2 · answered by e_kueh 2 · 0⤊ 0⤋
When you say that the second boat observes a velocity it means that you're implicitly using a reference frame in which the second boat has zero velocity.
So, let v2 be the velocity of the second boat. Then v1-v2 = V
v1 and V are given so you can solve for v2.
2007-01-17 06:24:19 · answer #3 · answered by modulo_function 7 · 0⤊ 0⤋