Heres the Simulation of Coriolis Effect So for example you are from Antarctica and you will go to iceland if you go straight, the spin of earth affects it, landing you to Eastern Canada Coriolis effect is also the cause of magnetic field, the spin may cause the outer core liquid move, creating earthquakes sometimes and this is the cause of magnetic field, thats why venus and mercury having weak magnetic field, except for mars, which having weak magnetic field but spins 30 minutes more than earth's, so whats wrong in there? its because mars dont really have much of iron and nickel (on i think). but the truth is here "Unless Mars has a molten iron/nickel core (and I'm pretty-sure it doesn't) whose spin differential creates a dynamo effect to generate a magnetic field (which is what protects Earth's atmosphere), our sun's solar wind will make creating new air on the red planet pointless, since it will just get blown away again." said here: science.time.com/2013/07/23/revealed-how-mars-lost-its-atmosphere/ or here: https://www.google.com.ph/search?q=why+doesn%27t+mars+have+a+magnetic+field&spell=1&sa=X&ei=hDRKVdrzJOPBmwX56IDADg&ved=0CBkQBSgA&biw=1280&bih=923 Also if the spin is too fast and the radius is too big (eg. jupiter) and/or the object move slowly, it will not make a curve line, instead it will make a spiral