In: Physics
Two boat landings are 4.8 km apart on the same bank of a stream that flows at 4.6 km/hr. A motorboat makes the round trip between the two landings in 2.5 hr. What is the speed of the boat relative to the water? answer in units km/h
Let the speed of boat be v.
time taken = 4.8/[v+4.6] + 4.8/[v-4.6]
2.5 =4.8/[v+4.6] + 4.8/[v-4.6]
2.5 = 2v*4.8/[v^2 - 4.6^2]
v^2 - 4.6^2 = 3.84v
v = 6.9 km/h answer