how to change velocity unity code example

Example 1: unity how to set rigidbody velocity

Vector3 velocity = new Vector3(10f/*x*/, 10f/*y*/, 10f/*z*/);
GetComponent<Rigidbody>().velocity = velocity;

Example 2: unity how to get player velocity

var vel = rigidbody.velocity;      //to get a Vector3 representation of the velocityspeed = vel.magnitude;             // to get magnitude