View Full Version : Carlos runs with a velocity
gbedenba
Sep23-09, 08:27 PM
1. The problem statement, all variables and given/known data
Carlos runs with a velocity of = (6 m/s, 25° north of east) for 10 minutes. How far to the north of his starting position does Carlos end up?
2. Relevant equations
3. The attempt at a solution
I thought maybe you would solve this problem like you do for x and y components? if so...where does the 10 min. go?
kuruman
Sep23-09, 08:44 PM
You do have to solve considering x and y components. The time goes in the relevant kinematics equations of motion. What are they?
gbedenba
Sep23-09, 08:54 PM
V = Vo + at
X - Xo = Vot + .5at2
v2 = vo2 + 2a(X - Xo)
X - Xo = .5(Vo + V)t
kuruman
Sep23-09, 08:59 PM
There is also a similar set of equations for the y direction. What should you use for the acceleration in the x and y direction?
gbedenba
Sep23-09, 09:00 PM
i have no clue...i am confused
kuruman
Sep23-09, 09:04 PM
Read the problem. Draw North-South and East-West axes. Can you picture in your mind how Carlos is moving? Reread the problem. Is the Carlos' sped increasing, decreasing or staying the same? Does his direction of motion change?
gbedenba
Sep23-09, 09:08 PM
I think his speed is staying the same... doesn't his direction stay the same as well
kuruman
Sep24-09, 05:04 AM
Yes, his speed and direction stay the same. This means that his velocity does not change. If his velocity does not change, what can you say about his acceleration?
gbedenba
Sep24-09, 08:32 AM
acceleration is zero
kuruman
Sep24-09, 08:40 AM
Very good. Now put zero in the place of acceleration a in the kinematic equations and write one set for the x-direction and a second set for the y-direction.
gbedenba
Sep24-09, 09:13 AM
which equation do I use? is there a way you could show me the first step?
kuruman
Sep24-09, 02:17 PM
V = Vo + at becomes V = Vo + 0*t becomes V = Vo.
Now that you know that V = Vo, replace V in the other three equations and replace a with zero like I did above.
X - Xo = Vot + .5at2
v2 = vo2 + 2a(X - Xo)
X - Xo = .5(Vo + V)t
Then repeat with y replacing x everywhere.
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