Solving for Particle A's Speed with Respect to Particle B

[bluetriangle]

Very simple question but I am confused... I am asked to find Particle A's speed with respect to Particle B. What does this mean?

I am given:
Particle A: (15i - 10j) or 18.03 m/s
Particle B: (5i + 15j) or 15.81 m/s

I just don't understand what I'm being asked to find and how to go about solving for it...
Thanks

 

[berkeman]

Very simple question but I am confused... I am asked to find Particle A's speed with respect to Particle B. What does this mean?

I am given:
Particle A: (15i - 10j) or 18.03 m/s
Particle B: (5i + 15j) or 15.81 m/s

I just don't understand what I'm being asked to find and how to go about solving for it...
Thanks

Welcome to the PF.

To get the speed of one "with respect to the other", just do a vector subtraction of their two vector velocities. :-)

 

[bluetriangle]

So if I'm trying to find Particle A in terms of B would I do A - B or B - A?

 

[mathman]

It doesn't matter. Speed is absolute value.

 

[bluetriangle]

Oh that's true, silly me. Thankyou!