Newton's 2nd Law & Inclined Ramp

AI Thread Summary
An astronaut's weight in the midpoint between two equally massive stars is effectively zero due to gravitational forces canceling each other out. For the inclined ramp problem, the first part involves calculating the coefficient of kinetic friction (mu) between a 75 kg box and a 25-degree ramp, resulting in a value of 0.061. The second part requires using this mu to determine the acceleration of a 175 kg box on the same ramp, which is calculated to be 1.54 m/s². To solve part b, it's essential to apply a free body diagram to visualize the forces acting on the box, particularly focusing on the force of friction. Understanding these concepts will clarify the solution process for both parts of the problem.
Mayy
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Well these two problems were from my quiz, and if I don't find out how to solve them soon, I'm going to spend my whole weekend thinking about them. D8 I'll try to remember the problems as best I can.

1) An astronaut is in space, in the midpoint of two stars that have the same mass. If all other stars are an infinite space away, how much does the astronaut weight? Explain.

2) A 75 kg box is on an inclined ramp that has an angle of 25 degrees. Its acceleration is 3.6 m/s/s.
a) Find mu of k between the box and ramp.
b) If the mass is 175 kg, what is its acceleration?

The answers to #2 are (a) .061, (b) 1.54 m/s/s
I just don't understand how to do part b. I got as far as finding sin, cos, and Fn, but I got stuck at finding Force of friction. I gave part a, just in case it's needed to solve b.
 
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Please show your work and then we can see where you are getting stuck.

For #2, part b presumably uses the same mu as you found in part a.
 
Always use a free body diagram for the questions like 1.Where there is a force acting on something, so you can have a clear map of forces..
 
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