## anonymous one year ago Why would Fx and Fy = 0 when you're moving an object at a constant velocity? Problem: 14kg mower being pushed at a 45degree angle from above with a force of 88N, mg=137.2, A) Find Ff B) Find Fn

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1. Photon336

For your first question we need to go into the nuts and bolts of the formula itself $F = ma$ this formula tells us that a force is equal to the product of the mass times the acceleration. Sometimes we have multiple forces and in multiple directions too. so we need to do the following. dont be to imitated by these formulas all they say is that in the X direction you add up all the forces in the x direction to find the net force in the X direction. Same for the Y. We do this because force is a vector it has both magnitude a value and a direction. these forces to my knowledge are independent of one another. $F _{nety} = F _{y}1 +F _{y2}...$ $F _{netx} = F_{x1} +F_{x2}... n$

2. Photon336

|dw:1441390450698:dw| once you find both Fnet X and Fnet Y you can imagine that it would look something like a right triangle so to find the magnitude total force. you take the values for Fnetx and F net Y and do the following similar to this equation $a ^{2} + b ^{2} = c ^{2}$ $Fnet = \sqrt{ (fnetx)^{2}+(Fnety)^{2}}$

3. Photon336

Okay so now let's get back to F = ma so this is telling us the following acceleration is equal to the change in velocity with respect to time. so in other words, for there to be acceleration, there must be a change in velocity in some time frame. $a = \frac{ dV }{ dt }$

4. Photon336

now if we are moving something with a constant velocity, we are applying a force to it. let's say we are moving that in the x direction. now if we are moving this at a constant velocity this means that our velocity isn't changing so that must mean that $a = \frac{ o }{ dt } = 0 ; dV = 0$ dV = 0 ,so acceleration must be zero. let's put this into our formula $F = (0)a = 0$ this means that our net force is zero. now let's say if we're moving this object only in the x axis like take the example if we're just sliding an object, are we moving it in the y axis? are there any forces being applied there? you also have to know where the forces are being applied. if there aren't any forces being applied in that direction then it's zero. |dw:1441391053367:dw| we usually have two forces in the y axis generally: they are the Fn normal force which is the force that's perpendicular to the surface and, the force of gravity which always points downward. the force of gravity is equal to m*g where g is the acceleration due to gravity. 10 meters/second squared. thus $F _{n} - F _{g} = 0$ this would be the case when an object is being moved at a constant velocity in the x direction but in the Y direction it's not moving period b/c no forces are acting on it.

5. IrishBoy123

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