Watching your fish swim in their tank, you notice that when one fish repeatedly jumps, it causes a standing wave given by the time-independent function
f(x)=asin(bx),with a = 0.015 m and b = 18.1 m−1 .
Part A
If the tank is 0.96 m long, determine the position of the first node, beginning with the node at one end of the tank.
Part B
If the tank is 0.96 m long, determine the position of the second node, beginning with the node at one end of the tank.

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Explanation:

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the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.