(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An initially stationary block of mass m lies on the floor. A force of magnitude 0.500mg is then applied at upward angle θ = 20°. What is the magnitude of the acceleration of the block across the floor if (a) μs = 0.620 and μk = 0.520 and (b) μs = 0.410 and μk = 0.310?

2. Relevant equations

Fx=.5mgcos20

Fy=.5mgsin20

3. The attempt at a solution

I first found my force in the x and y directions by using: Fx=Fcos(theta) = 0.5mgcos(theta)

Fy=Fsin(theta) = 0.5mgsin(theta). Since I had to find the normal force (in order to find out the static friction) i used: Fnet,y=may => Fn-Fg-Fy=may and since its not accelerating in the y direction ay=0 making: Fn=Fg+Fy => mg+0.5mgsin(theta), then i found the max static friction by using: Mu*normal force when i compared my max static friction to my Force in the x direction (since thats the only direction its moving), my static friction was less than my Fx, making a=0. And then i did that again for the second set of numbers for part b, got the same thing, a=0, but got it wrong. So i dont know what to do from there.

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# Homework Help: Magnitude of acceleration of a stationary mass

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