Do Jews and Muslims worship the same G-d? If so, do they understand G-d the same way? As a related point, is there any linguistic or theological connection between "Allah" and "Eloha" (or "Elohim")? Please explain.
In theory, Judaism and Islam worship the same Gd, since both religions believe that there is only one god.
However, in practice, the teachings of Islam and the teachings of Judaism are not always compatible.
The Rambam for instance writes some interesting and conflicting statements regarding Judaism and Islam.
On the one hand, Rambam states that Islam is monotheistic and there is no problem going to their mosques or interacting with them. However, Rambam also writes that it is forbidden to teach Torah to a Muslim because they believe that the Torah was corrupted. This is contrast with Christianity which the Rambam says is Avodah Zarah, however you are allowed to teach them Torah ,because they believe in the Truth of Moshe's words.
Secondly, I have heard from some Muslims that ideas about Gd that are acceptable to Jews, may not be acceptable to Muslims, and visa versa.