- #1

mcastillo356

Gold Member

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- Homework Statement
- We drive west at 75 km/h for 20 minutes and then follow a road that is oriented 40º to the south with respect to the original direction, driving at 90 km/h for some other 40 minutes. Calculate:

a) Total displacement

b) Celerity and velocity (vectorial) for all the travel

c) Draw a diagram of all the travel, including the length of each part of the displacement

- Relevant Equations
- Basic kinematics

I have not tried to make any calculation. It's nonsense, because I don't understand the statement. The first vector points to the west. Given a two dimensional coordinate system, the first vector is pointing to the left. I imagine geographical coordinates, north (+y), south (-y), west (-x), and east (+x). I think the first movement, in this coordinate system, is west (-x). But the second vector I think it can be drawn two ways; I mean that I can draw the second vector two valid ways, both starting at the end of the first vector: one, forward to the left, and down 40 degrees respect to the -x axis; and the second valid choice is to draw it backwards, I mean 40º respect the -x axis, but to the right. In this last choice, the car is also moving south, but turns back.

In both cases, the second vector moves 40 degrees downwards; but I think there are two possible choices respect the y axis: one pointing back to it; and the second (and also valid) following to the west.

Thanks!

In both cases, the second vector moves 40 degrees downwards; but I think there are two possible choices respect the y axis: one pointing back to it; and the second (and also valid) following to the west.

Thanks!