User:Jeff/Physics

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Problem 1
At time t=0, a 2.0 kg Jeff awakens to find himself at (0, 0) with an instantaneous velocity of 5.0 m/s in the –î direction. Exactly three forces are acting on Jeff: Fallie = 20 N ∠90°, Fgoogle = 10 N ∠210°, and Fbuttsex. At time t=3.0 s, Jeff's position is (13.5 cos 50° - 15, 13.5 sin 50°).

Part A
If the problem were changed such that Jeff was initially at rest, what would his position have been at time t=3.0 s? Where would he be if V(0) = 5.0 m/s ∠315°?

Part B
Find Jeff's acceleration vector and net force vector.

Part C
Find Fallie,x, Fallie,y, Fgoogle,x, Fgoogle,y, Fnet,x, Fnet,y, and Fbuttsex.

Part D
What was Jeff's position at time t=-1.0 s? What was his instantaneous velocity?

Part E
What is Jeff's minimum speed? At what position (x, y) and time t does Jeff experience this speed? What is his velocity?

Part F
Let Jeff's instantaneous velocity vector V(t) = Vx(t) î + Vy(t) ĵ. Which of the following is true?
 * Vx(tflip) = 0 for some tflip &gt; 0. The function Vx(t) is increasing.
 * Vy(tflip) = 0 for some tflip &gt; 0. The function Vy(t) is increasing.
 * Vx(tflip) = 0 for some tflip &gt; 0. The function Vx(t) is decreasing.
 * Vy(tflip) = 0 for some tflip &gt; 0. The function Vy(t) is decreasing.

Part G
Find tflip used in part F. What is Jeff's location and velocity at time t=tflip?

Part H
If Fallie disappears at time t=10 s, Fbuttsex goes away at t=20 s, and Fgoogle vanishes at t=30 s, what is Jeff's velocity at t=50 s?