When you hold a heavy ball in your hand at rest, the forces on the ball

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Originally Posted by moenicole8

When you hold a heavy ball in your hand at rest, the forces on the ball

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I would say anything at rest has a net force of zero.

Tut

Well on earth there is always the force of gravity. Your arm is exerting an equal and opposite force to hold the ball from falling.

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Originally Posted by NeedKarma

Well on earth there is always the force of gravity. Your arm is exerting an equal and oposite force to hold the ball from falling.

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Hi Karma,


Yes, there are many forces at work( including gravity) in this experiment. Realistically, if you think of the number of muscles at work in the human arm when holding a heavy object the sum of the forces becomes almost impossible to calculate.

I am assuming they are wanting you to come to the conclusion that all the forces will be in mechanical equilibrium. In other words, no matter how many forces are acting in this experiment they can all be incorporated into a single force.

One important stipulation to make mechanical equilibrium necessary is that the vector sum of the external forces acting on an object must be zero. That is why I gave the answer I did. I could be wrong.

Tut

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Originally Posted by TUT317

. I could be wrong.

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But you're not.

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Originally Posted by TUT317

Realistically, if you think of the number of muscles at work in the human arm when holding a heavy object the sum of the forces becomes almost impossible to calculate.

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I was thinking of the standard arrow up indicating the force of the arm acting on the ball and the arrow down indicating the force of gravity. I'm a very simple guy LOL.

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Originally Posted by NeedKarma

I was thinking of the standard arrow up indicating the force of the arm acting on the ball and the arrow down indicating the force of gravity. I'm a very simple guy LOL.

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Hi Karma,

That's OK. A lot of people would probably think that.

Tut