1. 01.25 points | Previous Answers SerPSET9 5.P 025 My Not The figure below show

Question

1. 01.25 points | Previous Answers SerPSET9 5.P 025 My Not The figure below shows a worker poling a boat-a very efficient mode of transportation-across a shallow lake. He pushes parallel to the length of the light pole, exerting a force of magnitude 224 N on the bottom of the lake. Assume the pole lies in the vertical plane containing the keel of the boat. At one moment, the pole makes an angle of 34.5o with the vertical and the water exerts a horizontal drag force of s 366 kg. (a) The water exerts a buoyant force vertically upward on the boat. Find the magnitude of this force 3109.31 x arry out a intermediate resuit rdig Your response is within 10% o the correct value. This may be due to round off error, or you cou d have a mistake in your calculation minimize roundoff error. N to at east accuracy b) Model the forces as constant over a short interval of time to find the magnitude of the velocity of the boat 0.405 s after the moment described. m/s

Explanation / Answer

given force applied parallel to the length of the pole , F = 224 N

drag force of water, horizontal D = -47.5 N

amgle pof pole with vertical ,theta = 34.5 deg

velocity magnitude, v = 0.857 m/s

mass of boat and cargo, m = 366 kg

a. let the buoyant force be B

as the boat has a acceleration

hence

from force balance

Fsin(theta) - D = 0

Fcos(theta) + B = mg

hence

B = mg - D/tan(theta) = 3521.347 N

b. when we consider forces to be constant for a small time, then speed of the boat will decrease becaus eof drag ( as applied force has been removed)

hence

deceleration = D/m = 0.1297 m/s/s

initial speed, u = 0.857 m/s

final speed v = u - at, t = 0.405 s

hence

v = 0.804438 m/s

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