Create user-controlled physics interactions:

// Add force on key press
scene.onKeyboardObservable.add((kbInfo) => {
    if (kbInfo.type === BABYLON.KeyboardEventTypes.KEYDOWN) {
        switch (kbInfo.event.key) {
            case "ArrowUp":
                sphere.physicsImpostor.applyImpulse(
                    new BABYLON.Vector3(0, 0, -10),
                    sphere.getAbsolutePosition()
                );
                break;
            case "ArrowDown":
                sphere.physicsImpostor.applyImpulse(
                    new BABYLON.Vector3(0, 0, 10),
                    sphere.getAbsolutePosition()
                );
                break;
            case "ArrowLeft":
                sphere.physicsImpostor.applyImpulse(
                    new BABYLON.Vector3(-10, 0, 0),
                    sphere.getAbsolutePosition()
                );
                break;
            case "ArrowRight":
                sphere.physicsImpostor.applyImpulse(
                    new BABYLON.Vector3(10, 0, 0),
                    sphere.getAbsolutePosition()
                );
                break;
            case " ": // Space key
                sphere.physicsImpostor.applyImpulse(
                    new BABYLON.Vector3(0, 10, 0), // Jump
                    sphere.getAbsolutePosition()
                );
                break;
        }
    }
});