Can i use my ipad adapter cube and a usb cord together without any damage to the phone?
The short answer is that any USB charger is safe with any USB device; a smaller (iPhone) charger may not charge a bigger (iPad) device. You can also connect your device via a USB extension cable.

The longer version is that Apple's USB chargers (whether sold with the iPhone, iPod Touch, iPad, Apple Watch, or new MacBook) are all essentially the same, the difference is how much electrical current they can supply. The chargers are all regulated (meaning they incorporate circuitry to maintain a constant voltage), which means the connected device will simply draw as much current as it needs and no more.

This means you can easily charge a lesser device with a greater charger; a MacBook (the new USB-C MacBook, not the older MagSafe models!) charger will quite safely charge an iPhone, as will an iPad charger. (You will, of course, need a USB-C to USB adapter, as the charger has a USB-C port and Apple doesn't yet make USB-C lightning cables.)

You can also charge a greater device with a lesser charger, though charging will be slower. An iPad will work with an iPhone charger, but will charge much more slowly, or not at all. An iPhone charger will not damage the new MacBook, but it also probably won't supply enough power for it to run, let alone charge.

You can also connect the device to the charger with a USB extension cable (though not a hub!), but I'd recommend not exceeding 5 m total cable length (from the USB port on the charger, to the port on your device).

Other USB devices can also be powered or charged with an Apple USB charger; I often use my iPhone chargers to charge my 3G WiFi modem, charge Bluetooth headphones, and run a Raspberry Pi.