Posted by bobjahng on .
In a World Cup soccer match, Juan is running due north toward the goal with a speed of 7.80 m/s relative to the ground. A teammate passes the ball to him. The ball has a speed of 13.6 m/s and is moving in a direction of 32.5 degrees east of north, relative to the ground.
a)What is the magnitude of the ball's velocity relative to Juan?
b)What is the direction of the ball's velocity relative to Juan?
How do you start this off? I found the y component and subtracted it to find the answer for the first part, but it says that my answer is wrong.

physics 
bobpursley,
a) ball relativeground=Juansspeed+ball relative to Juan
13.6Cos32.5N + 13.6Sin32.5E =7.8N+ballrelative to Juan
ball relative to Juan= (13.6Cos32.57.8)N+13.6Sin32.5E
so figure out the N component, then magnitude= sqrt (Ncomp^2+Ecomp^2) 
physics 
bobjahng,
i got the right answer for part a (8.18)
now how do i do part b? 
physics 
bobpursley,
you have the vector:
Ncomp, E component
relative to Juan, going N, so it is E of him by theta, where tantheta=Ecomp/Ncomp 
physics 
billy,
i cant get part b!!!!!!! im completely lost >.<

physics 
Juan,
Hi Chris

physics 
El Piton,
On that Kobe System.
Or Linsanity 
physics 
Annie,
Make sure you're putting the parenthesis in the correct place. Such as for part A, the formulas should be:
a) (ball relative ground) = (Juan's speed)+ (ball relative to Juan)
(13.6Cos(32.5))N + (13.6Sin(32.5))E =(7.8)N+(ball relative to Juan)
ball relative to Juan= (13.6(Cos(32.5))7.8)N+(13.6Sin(32.5))E
so figure out the N component, then magnitude= sqrt (Ncomp^2+Ecomp^2)