Problem $2$: A charged object is moving in a region in space with a magnetic field vec$(B).$ There is no other force acting on the object. As a result, the particle's path is a circle of radius $R.$ Determine the direction of the magnetic field. Express your answer in terms of hat$(r),$hat$(),$ and hat$(k).$ Include the negative sign in front of the unit vector as needed.

Figure $1.$ The direction of vec$(B)$ is:

Figure $2.$ The direction of vec$(B)$ is: