Why there is no horizintal acceleration?

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When a stone is thrown off a cliff, it experiences vertical acceleration due to gravity but not horizontal acceleration once released. The absence of horizontal acceleration is explained by Newton's first law of motion, which states that an object in motion will remain in motion unless acted upon by an external force. If the stone is pushed horizontally before being released, it may initially have horizontal acceleration, but this ceases once it is let go. In real-life scenarios, air resistance can cause a small deceleration in the horizontal direction, but this effect is typically minimal. Understanding these principles clarifies the dynamics of projectile motion.
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When a stone is thrown over a clift, there is vertically acceleration, I don't understand why there is no horizintal acceleration? :confused:
 
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Hi London! How about my friend the BigBen? :biggrin:

Well, that depends on HOW do you throw the stone.If you merely leave it falling free it won't have any horizontal acceleration. But if you push it horizontally probably it will have horizontal acceleration.
 
Clausius2 said:
But if you push it horizontally probably it will have horizontal acceleration.
As soon as you let go of the stone, it will no longer have horizontal acceleration. This is due to Newton's 2nd law of motion, most videly known as F=ma. If there are no forces acting on the object, it will not accelerate. It's called inertia, and works independantly for each axis of any coordinate system.
EDIT: actually, inertia is Newton's first law, and the 2nd law (F=ma) is a generalization of the first.

Note however, that the above is an approximation: in real life, you usually have air, which causes a drag force propotional to the object's velocity. So in that case there is a horizontal acceleration (deceleration), but it is usually very small (because the horizontal velocity is usually small). You also have drag in the vertical direction, which is why you get a terminal velocity (= a velocity where the vertical drag balances out the object's weigth, so the object can't accelerate any further in the vertical direction).
 
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alpha_wolf said:
As soon as you let go of the stone, it will no longer have horizontal acceleration. This is due to Newton's 2nd law of motion, most videly known as F=ma..

Oops. Thanks alpha. Well, eeemmmmm... I meant the deceleration due to air drag effects :rolleyes: :-p
 
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