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

A 9 N horizontal force F pushes a block weighing 13.0 N against a vertical wall (Fig. 6-21). The coefficient of static friction between the wall and the block is 0.62, and the coefficient of kinetic friction is 0.42. Assume that the block is not moving initially.

(Image attached)

Determine the normal force that the wall exerts against the block

9 N (It is the same amount pushing against the block- they should be equal)

Determine the blocks acceleration

m/s^2

2. Relevant equations

Fk= (Coefficient of K)*N

F=ma

Max= Push- normal

May= Static- mg

3. The attempt at a solution

Alright, I began drawing a force graph. On this graph weight faces down, normal force is exerted left (see attachement), static force is exerted up, and push force is exerted right. Determining the acceleration means horizontally, because the acceleration vertically is 9.8. Now, looking at my equations, only one contains 'a': F=ma. So, what do I know in this equation? I can get mass from the 13 N weight. 13/9.8= 1.32653 mass. That just leaves me to find the force. Going back, the acceleration I am trying to find is horizontal. So, I need to use the push-normal to get my total force. Here's my big problem, don't the push force and the normal force equal each other? So that would leave me with an Ma= 0. What does this mean? What have I done wrong?

Thank you in advance!

~Phoenix

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# Homework Help: Push a Block against a Wall- Static Friction

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