What do you think might have been some of the events in europe that motivated japan to enter the war on the side of the axis powers?

 It all boils down to the Japanese quest to be considered a 'ittokoku' or 'first rank nation'. Since the Meiji Restoration, Japan's foreign policy had been geared towards achieving that end. They had joined the ranks of colonial powers and wished to enjoy the status of other imperial nations like Britain, Germany and the US. 

They had fought on the side of the Allies during WWI and expected that to lead to recognition as one of the great powers. However, when the Japanese delegation proposed a clause on racial equality in the Paris Peace Conference they were largely rebuffed by the Western powers. This was followed by the Washington Naval Treaty of 1922 where Japan felt unfairly treated again. This led Japan to conclude that their interests lay apart from their former allies. 

Actually, they had little in common with the other Axis powers and their aims were largely unconnected; they merely wanted a free hand in their own spheres of interest. After they declared war there was little military co-ordination; Germany was useful as another means of pressure on Great Britain and the U.S. whose colonies Japan were looking to take.The other Axis powers saw Japan in the same terms. 

Of course there are many other contributory factors but these were the major ones. 

Hope that helps :-)

Japan was using the other Axis powers as a means to become a more powerful nation.

Bis your correct answer

Because he is hungry