MHB Friction Mechanics: Solving for Block's Speed at Point A

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To determine the speed of a wooden block sliding down a rough slope, the block's mass is 3.5 kg, and it initially moves up at 20 m/s before coming to rest 25 m up the slope, which is inclined at 29 degrees. The coefficient of friction was calculated to be 0.554, leading to an acceleration of -8 m/s². Using the equation v² = u² + 2as, the acceleration was further analyzed, resulting in a recalculated coefficient of friction of 0.36. The discussion emphasizes the need for accurate calculations to find the block's speed at point A on its return. The focus remains on solving the mechanics of motion under frictional forces.
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A wooden block of mass 3.5kg is sliding up a rough slope and passes a point A with speed 20m/s. The slope is at 29 degree to the horizontal. The block comes to rest 25m up the slope. Find its speed as it passes point A on the way down.
I calculated coefficient of friction = 0.554.
U=20m/s v= 0 and s= 25m.
By using v^2= u^2+2as, I got a= -8m/s^2.
I can't calculate after this.
Pls help
 
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upslope …

$a = \dfrac{0^2-20^2}{50} = -8 \, m/s^2 = -10[\sin(29)+\mu\cos(29)] \implies \mu = 0.36$

try again …
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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