As we know that the earth is rotating at a very high angular velocity and as we are on the earth and also rotating with the same speed so the net speed we feel is zero.
Now suppose there is a car and a man standing on roof of the car.car is running.Now man is at rest with respect to the car,as is the case with a man standing on the surface of the earth.Now if the man on the roof of the car jumps upwards in the air the car will move forward and he will fell on the earth behind the car.It means he will not be on the same point where he was before the jump.Now if the man on the surface of the earth jumps in the air why he comes back on the same spot and the earth does not move away from him and he doesn't fell due to inertia ?