Simple Body

var config = {
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    parent: 'phaser-example',
    physics: {
        default: 'impact'
    },
    scene: {
        preload: preload,
        create: create
    }
};

var game = new Phaser.Game(config);

function preload ()
{
    this.load.image('block', 'assets/sprites/block.png');
}

function create ()
{
    this.impact.add.image(0, 300, 'block').setVelocityX(100);
}