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

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Homework Help Overview

The discussion revolves around a physics problem involving a sled being pulled across a smooth ice surface with a force applied at an angle. Participants are exploring the reasoning behind using the cosine function to find the x-component of the force acting on the sled.

Discussion Character

  • Conceptual clarification, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the necessity of using cosine to resolve the force into its x-component, with some suggesting that drawing vectors may aid understanding. Questions arise regarding the relationship between force, mass, and velocity, with attempts to clarify the distinction between acceleration and velocity.

Discussion Status

The conversation is ongoing, with some participants offering insights into the relationships between force, mass, and acceleration. There is recognition of the complexity involved in finding the x-component of the force, and some participants are actively working through their understanding of the concepts involved.

Contextual Notes

Participants are navigating the implications of the problem's setup, including the angle of the applied force and the definitions of acceleration and velocity. There is a sense of urgency in some posts, indicating that participants are balancing their understanding with time constraints.

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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?
 
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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.
 
and i was in a hurry i have one more question

magnitude/mass finds the velocity? or what does it find?
 
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! :)
 
wut? you just stabbed me with a knife just by confusing me
 
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
 
exactly! :D the tough thing is finding the x-component Force though.
 

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