What is meant by the statement 'gravity is not uniform'?
It means that at a particular place under the consideration the acceleration due to gravity ( g ) is not the same at some other place. for example, the value of g at the North pole is 9.832m/s2 and at New York it is 9.803m/s2 and at Greenland it is 9.825m/s2 and at Calcutta it is 9.788m/s2 .