Sliding sound while pressing the acceleration pedal
 

HI,
I purchased a brand new audi a4 2015 , quatro. When ever i start the engine and put on drive and press the acceleration pedal i hear a 2 time sliding sound(which is something like a belt slipping off the wheel while rotating), it that normal?? This sound comes only when i stop and start engine with a gap of at least 15-20 minutes. Can any one help me regarding this issue .

Thanks
John