# Because of the rotation of the earth, an object can be thrown farther if it is thrown west?

ummm not too sure maybe someone can share some info on the subject.

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• Anonymous

No, but the opposite statement is true (slightly). The rotation of the earth has two impacts on us in our rotating reference frame:

Centrifugal pseudoforce, which mitigates gravity somewhat and pushes objects towards the equator a teensy tiny bit. Doesn't depend on your velocity (in the reference frame), so it isn't directly relevent to this problem.

Coriolis pseudoforce. Proportional to MINUS the cross product of the earth's rotational velocity (vector pointing due north) and the objects velocity. If you are at the equator and throw something east, the coriolis force pushes it UP. If you throw it west, the coriolis force pushes it DOWN. So the eastward throw will go a bit further.

I don't think the effect is sufficient to matter much if you're throwing something, but artillerymen have to factor stuff like that in if they want to achieve perfect accuracy.

Edit: I screwed up my calculation the first time through--there's a minus sign in the formula that I missed. It's correct now.

• Steve
Lv 7

False. The object thrown east will have a greater velocity and its weight will be reduced by (V+Vo)²/r, where V = local earth velocity, Vo = horizontal velocity of object, and r = local distance to the axis of the earth.

The object will experiance a smaller value of g than a stationary object and smaller yet than one thrown to the west. Accordingly, its time of flight will be greater as will the distance traveled.

In fact, this principle is used on every space launch to gain the advantage of the eastward movement of the earth's surface.

• Cirric
Lv 7