Rowing Speed of River Veloc Assume that the water ha orientation of her boat are
ID: 1879276 • Letter: R
Question
Rowing Speed of River Veloc Assume that the water ha orientation of her boat are also shown. Select the direction (Ie, J, or C, or..) in order to cross the river in The motion of the boat results from adding the velocity of the water to the velocity of the boat with respect to the water. Sutmit Ansar Answer Submitted: Your final submission will be graded after the due date. Tries 1/99 Previous Tries s uniform velocity, represented above by the vector labeled B. The rowing speed of the girl and a set of possible the shortest time. ing orientation will the girl land on the opposite shore directly across from her starting position, neither upstream or downstrea Submit Answer Tries 0/99 Select an answer for each below Time to row across for K is.... for The distance traveled in crossing for H is.... for D Time to row across for A is for C Time to row across for A is for J : For an observer on shore, the speed of the boat for F is... for D Submit Answer Tries 0/99Explanation / Answer
given water has uniform velocity rewpresented by vector B
let x displacement be the distacne required to cross the river
let the velocity of the boat wrt to the ground be v at angle theta with the x axis
then
time taken to cross the river = t
then
x = vcos(theta)*t
vertical displacement along the river = y = (u + vsin(theta))*t
sqrt(x^2 + y^2) = v*t
t is minimum when y is 0
hence
sin(theta) = -u/v
theta = -arcsin(u/v)
so -ve angle gets lower time
u = 2 units
v = 6 unmits
theta = -18.43 deg
so time of H is lowest
the C and A, then D, K , J
tiem form K is less than J
distance in H is lower than D
tiem for A is more than time for C
A is less thasn J
for offshore person, speed at F is more than speed at H
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