The position coordinates of a particle moving in a 3D coordinate system is given by X=a cos t, Y=a sin t and Z = a t. The speed of the particle is
a. 
a 
b. 
a 
c. 

d. 
2a 
The position coordinates of a particle moving in a 3D coordinate system is given by X=a cos t, Y=a sin t and Z = a t. The speed of the particle is
a. 
a 
b. 
a 
c. 

d. 
2a 
v_{x }= −a sin t
v_{y}= a cos t
v_{z }= a
v = .