Finding acceleartion components

[ultrabionic_ang]

So the problem goes:

A proton, with rest mass 1.67x10^-27 kg, is moving at v=.9c (where c= speed of light) in the positive x direction, relative to the reference frame of a physics laboratory. Then, a constant force F=(-3.00 X 10^-12)i + (5.00 X 10^-12)j is applied to proton

a) find x and y comps of accl of proton after F was just applied

Bassically, i just used this equation to solve for x and y comps of accl:

F= (ma)/(1-(v^2/c^2))^3/2 and solved for a, and plugged in x and y comps..

is that right?

b) find the angle between F and the acceleration that was calculated in part a...

not sure how to go about that.. is the dot product of F and a taken in order to find the angle?

thanks!

 

[QuantumKing]

youve got the right idea for a)...except its the square root of (1-v^2/c^2)...so^1/2

and for b)..im supposing you have to find the force vector components..and then, you know