An angler sits stationary on shore watching a river flow by and notices a fish a
ID: 1406664 • Letter: A
Question
An angler sits stationary on shore watching a river flow by and notices a fish accelerating upstream at constant acceleration. the fish's water speed (speed according to the fish)at time tnot = 0. After accelerating for t1 = 7s the v1 = 5 ft/s. at time t1 the angler sees 2.5ft/s A). what is the speed of the river's current? b). what is the acceleration of the fish in the reference frame of the fish c). the acceleration of the fish in the reference frame of the angler. Compare this to the nswer from part c. d). howfar downstream the fish is from the angler's position on the bank at time tnot? e). the angle to hit the fish with a rock at tfinal=10s. f0. the velocity of the thrown rock as it leaves the angler's hand? the rocks trajectory is initially horizontal and the rock leaves the angler's hand at waist height hnot = 3ft above the level of the fish swimming at the surface of the river
Explanation / Answer
a. speed of river = V1-V2 = 7-5 = 2 ft/s
b. accleration of the fish = v/t = 2.5/7 = 0.357 ft/s^2
c. Accleration W r t Anglre = 2/7 = 0.285 ft/s^2
on comparing af/af' = 0.357/0.285 = 1.25
D. use X = vot + 0.5 at^2
X = ( 5* 10) + ( 0.5* 0.357 * 10*10)
X = 67.85 ft
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e. tan theta = ay/ax = 0.285/0.357
tann theta = 0.798
theta = 38.6 deg
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