Calculate Recoil Velocity: 4.85kg Stone & 102kg Canoe

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The discussion revolves around calculating the horizontal recoil velocity of a canoe and person after throwing a stone. The stone's mass is stated as either 4.85 kg or 4.58 kg, leading to confusion about which value to use. The initial calculations yield a recoil velocity of -0.28327 m/s, which the poster believes is incorrect. Participants suggest checking for copying errors in the problem statement, as this may affect the accuracy of the calculations. Clarifying the mass of the stone is essential for resolving the issue.
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Homework Statement



First: My course has sig figs disabled. We are recording all that is shown in calculations. Its my instructor's choice, not mine. Please do not lecture on sig figs. I know already. ;)
Problem:
A person stands in a stationary canoe and throws a 4.85-kg stone with a velocity of +7.73 m/s at an angle of 35.3 ° above the horizontal. The person and canoe have a combined mass of 102 kg. Ignore air resistance and effects of the water and find the horizontal recoil velocity (magnitude and direction) of the person and canoe.


The Attempt at a Solution



horizontal velocity = velocity of 7.73m/s * cos 35.3 = 6.3087
mass of stone 4.58kg * horizontal velocity of 6.3087 = 28.894 kg m/s
28.894 kg m/s = 102kg * recoil velocity
28.894 / 102 = recoil velocity = -0.28327 m/s This is incorrect. What have I done wrong? The negative is for the opposite direction movement.
 
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Do you know the answer? Also, check the exact wording of the problem once more, in case something has been missed.
 
Jacque77 said:

Homework Statement


A person stands in a stationary canoe and throws a 4.85-kg stone with a velocity of +7.73 m/s at an angle of 35.3 ° above the horizontal. The person and canoe have a combined mass of 102 kg. Ignore air resistance and effects of the water and find the horizontal recoil velocity (magnitude and direction) of the person and canoe.


The Attempt at a Solution



horizontal velocity = velocity of 7.73m/s * cos 35.3 = 6.3087
mass of stone 4.58kg * horizontal velocity of 6.3087 = 28.894 kg m/s
28.894 kg m/s = 102kg * recoil velocity
28.894 / 102 = recoil velocity = -0.28327 m/s This is incorrect. What have I done wrong? The negative is for the opposite direction movement.

Presumably, either 4.85 kg. or 4.58 kg. is correct for the mass of the stone. (I also want to stay away from someone who can throw an 11 pound stone that fast...). Somewhere you have a copying error, which may explain why the computer didn't like your answer...
 

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