Silly doubt I encountered.Please help...

[nike_nikup]

Recently,while travelling in the bus, I observed the insects flying .How is it possible that they do not hit the back window ?They aren't in contact with the bus. So inertia shouldn't have any effect on them as they aren't in contact with the bus.As the bus moves forward at high speed, the insect should be hit by the back part of the bus.

[Michael Steen]

They are in contact with the bus--with the air inside. Were they somehow suspended in a vacuum (I don't know how they'd do that), they would indeed hit the back of the bus when it accelerated. But the air is a very important part of the bus and moves along with it; that's the reason you don't feel a breeze on your face when the bus moves forward (assuming the windows are closed).