Force Acting on Pipe: Why is Velocity Difference (25-25cos115)?

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The discussion centers on the calculation of change in velocity in a physics problem involving force acting on a pipe. Participants question the author's expression for change in velocity, specifically why it is given as (25 - 25cos115) instead of the expected (25cos115 - 25). There is agreement that the calculation should reflect the correct final and initial velocities. Additionally, it is noted that the force exerted by the vane on the water should be considered negative when accounting for direction. The conversation highlights the importance of accurately determining velocity differences in force calculations.
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Homework Statement


why the author gave the change in velocity as (25- 25cos115) , shouldn't it be final - initial velocity , which is (25cos115 -25) ?

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foo9008 said:
why the author gave the change in velocity as (25- 25cos115) , shouldn't it be final - initial velocity , which is (25cos115 -25) ?
I agree. At that point, the author is calculating the force the vane exerts on the water, which with positive to the right should be negative.
 
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