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When a body lies on the surface of the Earth it is under the influence of gravity. The force on the body due to gravity causes it to exert a force on the ground and the normal reaction acts in the opposite direction causing the resultant force on the body to be zero.

However, how can the body exert a force on the ground when it does not have any acceleration? Since force equals mass times acceleration how does a body without acceleration experience a force?

jerry
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When a body lies on the surface of the Earth it is under the influence of gravity. The force on the body due to gravity causes it to exert a force on the ground and the normal reaction acts in the opposite direction causing the resultant force on the body to be zero.

Correct

However, how can the body exert a force on the ground when it does not have any acceleration? Since force equals mass times acceleration how does a body without acceleration experience a force?

But you do have an acceleration, $g$, which you stated in the first paragraph (the force on the body due to gravity...). And this force is equal and opposite to the normal force: $$ \mathbf F_{g} = -\mathbf F_N \\ mg\left(-\hat{z}\right) = -mg\hat{z} $$ That the net force is zero only means that the object is not accelerating, not that there are no forces acting on it.

Kyle Kanos
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Newton's second law of motion states this (verify on Wikipedia): $$\vec F_{net} = m\vec a$$ Here, $\vec F_{net}$ is zero, so $\vec a$ is zero too. Going back in reverse (what you did in question), $\vec a = \frac{\vec F_{net}}{m}$ can only deduce that the body is experiencing no net force. That's it.

Feel free to use Law of Gravitation, Coulumb's Law etc when the force in question isn't the sole cause of the effect. Newton's second law of motion can't help here.

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how can the body exert a force on the ground when it does not have any acceleration?

The body has acceleration relative to the earth $$ F_{earth} = F_{object} \\ m_{earth} * a_{earth} = m_{object} * a_{object} $$

Since force equals mass times acceleration (magnitude-wise) how does a body without acceleration experience a force?

The sum of forces in the body equals the external force acted on it.

arvil
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The reaction force of a body can not exist without the action force,this is precisely why the body experiences a press on it, the reason it doesnt accelerate is because the forces balance,but that doesnt mean the gravity would seize to act thus the reaction felt by the object

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When a body lies on the surface of the Earth it is under the influence of gravity. The force on the body due to gravity causes it to exert a force on the ground and the normal reaction acts in the opposite direction causing the resultant force on the body to be zero.

Correct

However, how can the body exert a force on the ground when it does not have any acceleration? Since force equals mass times acceleration how does a body without acceleration experience a force?

But you do have an acceleration, g , which you stated in the first paragraph (the force on the body due to

Kyle Kanos
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Malika
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