Can I get the speed of a rigidbody object? Or Set the speed of it?

Can I get the speed of a rigidbody object? Or Set the speed of it?

yes, the rigidbody has a property called velocity which you can get if you use GetComponent on a varible with type rigidbody and then call for the property.

As such:

private Rigidbody someRigidBody;
private float someRigidBodySpeed;

void Awake()
{
    //Checks if the component actually exists at all
    if (GetComponent<Rigidbody>() != null)
    {
        //Set the object you just proved existed
        someRigidBody = GetComponent<Rigidbody>();
    }
    else
    {
        //If it does not exist report the problem ( normally a null would cause a 
        //crash/null reference exception during compilation ) depending on what's
        //happening. Both should be avoided
        Debug.LogError("Rigidbody missing in , can put name of class here,  in awake method");
    }
}

void Update
{
    //Extracts the speed from the rigibody 
    someRigidBodySpeed = someRigidbody.velocity;
}

For more information , or if I made some syntax error please look here Setting the speed you will need to do with physics , like AddForce, you are physically manipulating objects that way OR you can overwrite the velocity property since it has write permissions (as the first link shows)