A woman starts to swim directly across a 5.2-km-wide river. Her speed with respect to the water is 1.9 m/s. The river current carries the woman downstream at a speed of 0.91 m/s.(a) How much time does it take her to cross the river? in sec(b) How far downstream will the river carry her by the time she reaches the other side of the river? in m

(a) the time needs for her to cross the river is 2736.8 s.

(b) the distance takes to reach the other side of the river is 2490.5 m.

Explanation:

given information:

woman's speed, v₁ = 1.9 m/s

the wide of river, s = 5.2 km = 5200 m

river's current, v₂ = 0.91 m/s

(a) How much time does it take her to cross the river?

s = v t

s = the displacement (m)

v = speed (m/s)

t = time (s)

s = v t

t = s/v

 = 5200/1.9

 = 2736.8 s

(b) How far downstream will the river carry her by the time she reaches the other side of the river?

s = v t

  = (0.91) (2736.8)

  = 2490.5 m

v=ir = 3x15 =45 v