Why Do We Multiply by Cos(35) to Find the X-Component of Force in Physics?

[godkills]

A 4.6 kg is pulled across a smooth ice surface. The force acting on the sled is a magnitude 6.2 N and points in a direction 35 degrees above horizontal. If the sled starts at rest, how fast is going after being pulled 1.15s?

I know the answer but question is why do I have to multiply the magnitude/mass times cost(35)?

cos 35 is the problem why do i have to do that?

 

[Rayquesto]

since the object the the force is exerting upon is horizontal, then the forces in the x direction still use cos x to get the forces in the x direction, but sin x to get the forces in the y direction. if you draw it out with four vectors, you may understand why, but ask after you draw them if you don't understand still. Even ask if you don't know what to draw.

 

[godkills]

and i was in a hurry i have one more question

magnitude/mass finds the velocity? or what does it find?

 

[Rayquesto]

magnitude of the force divided by the mass of the object is the acceleration, not the velocity. To find velocity is much more complex and I really don't know how to do it with just forces. You could find the kinetic energy and the potential gravitational energy to find velocity I think, or maybe motion in one dimension equations. You probably remember some of those. It's tough though. hm... Oh but then again if we know the time, then we could find velocity I think. let's think time velocity over time iis acceleration I think. let me look it up real quick. I am not completely sure if that's true. It's velocity over time is acceleration. I just looked it up. So, if you find the magnitude of the force divided by the mass of object, then you can multiply 1.15 seconds times magnitude/mass to get the velocity! :)

 

[godkills]

wut? you just stabbed me with a knife just by confusing me

 

[godkills]

okay i just figured out myself

question states how fast is it being pulled meaning the x component when it is being pulled

so you find the force of the x component which is cos(x) multiplying the force of the hypotneuse which equals to the force of x component

Now F = ma

Force/mass = Acceleration

Acceleration x time adding with initial velocity = final velocity

 

[Rayquesto]

exactly! :D the tough thing is finding the x-component Force though.