rbmove.cs

Update() {
	if (Input.GetKeyDown(KeyCode.W) || Input.GetKeyDown(KeyCode.A) || Input.GetKeyDown(KeyCode.S) || Input.GetKeyDown(KeyCode.D) || Input.GetKeyUp(KeyCode.W) || Input.GetKeyUp(KeyCode.A) || Input.GetKeyUp(KeyCode.S) || Input.GetKeyUp(KeyCode.D)) {
		stopRigidbody = true;
	}
}

FixedUpdate() {
	if (stopRigidbody == true) {
		rb.velocity = Vector3.zero;
		stopRigidbody = false;
	}
	float speedMag = targetVelocity - rb.velocity.magnitude;
	rb.AddForce(movingDirecion * speedMag, ForceMode.Force);
}