# Help finding average speed

chris_soft_engineer
The problem is:

A motorist drives south at 20.0 m/s for 3.00 min, then turns west and travels at 25.0 m/s for 2.00 min, and finally travels northwest at 30.0 m/s for 1.00 min. For this 6.00-min trip, find (a) the total vector displacement, (b) the average speed, and (c) the average velocity. Let the positive x-axis point east.

I need help figuring out the total vector displacement. I just want someone to explain how you find it and let me work it please.

thanks for the help

mathmike
you can use a cartisen coordinate system to figure out the vectors

you first travel south for 3600 meters, this would be (0 , -3600)

then you travel west for 3000 meters, add this to the first you have (3000 , -3600)

hen you travel 1800 meters at an angle of 45 degrees so you have ( 4272.292 , -2328)

you can do the rest right

chris_soft_engineer
That wasn't my question. My question is how do i find the total displacement.
Do i just add all of that together?

mathmike
yes that should do it

chris_soft_engineer
Thanks so much for the help. :rofl:

Townsend
chris_soft_engineer said:
That wasn't my question. My question is how do i find the total displacement.
Do i just add all of that together?

Adding the components will give you the total displacement vector. Are you sure that is what you want?

Perhaps you were thinking about the magnitude of the vector as well? Do you know how to find this?