# PhysicsCh3

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1. What are the two ways that a vector can be described?
• Magnitude and angle
• Components (X and Y)
• A+B = C
• Components: Ax+Bx = Cx , Ay+By = Cy
• Graphically: graphing from head to tail

• A-B = C
• Components: Ax-Bx = Cx , Ay-By = Cy Graphically: graphing from head to head
3. When adding vectors (componently), a vector with magnitude V making an angle θ with the x axis has what components?
Given the components, what is the vector's magnitude and direction?
• Vx = Vcosθ, Vy = Vsinθ
• V = √(V2x+V2y), tanθ = Vy/Vx
4. Projectile Motion - information without equations
• Break down into two motions (X and Y) which are completely independent of eachother.
• The Y motion has acceleration of -g
• The X motion has no acceleration!
5. Projectile Motion - equations based on components
• y = y0+V0yt-1/2gt
• Vy = V0y-gt
• Vy2-Vy02 = -2gΔy
• x = x0+V0xt
• Vx = V0x
6. How do an object dropped horizontally and thrown vertically compare?  Why?
They will both land at the same time, because the ONLY acceleration acting on both is -g.  It may start with V, but NOT ACCELERATE
7. What is relative velocity? How is it used practically?>
• Relative velocity is a reference to moving in/on something that is already in motion.
• Ex - walking 4m/s backwards on a train moving 8m/s forward
• Depending on which reference you are using the net velocity will be different!
 Author: victimsofadown ID: 203504 Card Set: PhysicsCh3 Updated: 2013-02-26 10:30:36 Tags: PhysicsCh3 Folders: Description: PhysicsCh3 Show Answers: