Version: 2022.1

# Rigidbody2D.velocity

マニュアルに切り替える
public Vector2 velocity ;

## 説明

Linear velocity of the Rigidbody in units per second.

The velocity is specified as a vector with components in the X and Y directions (there is no Z direction in 2D physics). The value is not usually set directly but rather by using forces. Disable drag in the Inspector to stop the gradual decay of the velocity.

```//Create a new 2D Sprite GameObject and attach this script to it.//This script moves a GameObject up or down when you press the up or down arrow keys.
//The velocity is set to the Vector2() value.  Unchanging the Vector2() keeps the
//GameObject moving at a constant rate.using UnityEngine;public class ExampleClass : MonoBehaviour
{
private Rigidbody2D rb;    private float t = 0.0f;
private bool moving = false;    void Awake()
{
rb.bodyType = RigidbodyType2D.Kinematic;
}    void Start()
{
gameObject.transform.Translate(0.0f, 0.0f, 0.0f);
}    void Update()
{
//Press the Up arrow key to move the RigidBody upwards
if (Input.GetKey(KeyCode.UpArrow))
{
rb.velocity = new Vector2(0.0f, 2.0f);
moving = true;
t = 0.0f;
}        //Press the Down arrow key to move the RigidBody downwards
if (Input.GetKey(KeyCode.DownArrow))
{
rb.velocity = new Vector2(0.0f, -1.0f);
moving = true;
t = 0.0f;
}        if (moving)
{
// Record the time spent moving up or down.
// When this is 1sec then display info
t = t + Time.deltaTime;
if (t > 1.0f)
{
Debug.Log(gameObject.transform.position.y + " : " + t);
t = 0.0f;
}
}
}
}
```