Why is this animation looks blury ? There is no motion blur in it

Human Retinal retention rate vs video frame rate vs speed of movement. Did you even notice that video of an airplane propeller, a helicopter's rotors, or a wagon wheel's spokes changing speed when they shouldn't, or look like they are moving backward or have some weird jittering? This is caused by the stroboscopic interaction of the frame rate/shutter speed/motion speed/and even how fast your eyes can decern movement. 

If you want the speed of the movement to stay the same, you have two choices: add motion blur or change the frame rate. Even the refresh rate of your computer monitor can cause this visual judder. 

To fix the problem and maintain smooth motion, change the speed of the camera move. Fast movement always looks a little better with some motion blur because our eyes do it for us automatically. The frame of the video helps fool our brains and increases the problem. 

I hope this helps.