Lets say that my desk can stand until 50 newtons. So I put my hand up to desk with 20 newtons,so third newton's law says that desktop will put force with 20 newtons my hand. After some seconds,I put force with 50 newtons,so my hand will feel 50 newtons too from the desk. After I put force of 55 newtons(so desk will broke). Theoritically my hand will feel 50,or 55 Newtons ?? Thanks.