Which statement best describes an atom? (2 points)
2 answers:
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The text does not specify whether the resistance R of the wire must be kept the same or not: here I assume R must be kept the same.
The relationship between the resistance and the resistivity of a wire is
where
is the resistivity
A is the cross-sectional area
R is the resistance
L is the wire length
the cross-sectional area is given by
where r is the radius of the wire. Substituting in the previous equation ,we find
For the new wire, the length L is kept the same (L'=L) while the radius is doubled (r'=2r), so the new resistivity is
Therefore, the new resistivity must be 4 times the original one.
The relationship between the resistance and the resistivity of a wire is
where
A is the cross-sectional area
R is the resistance
L is the wire length
the cross-sectional area is given by
where r is the radius of the wire. Substituting in the previous equation ,we find
For the new wire, the length L is kept the same (L'=L) while the radius is doubled (r'=2r), so the new resistivity is
Therefore, the new resistivity must be 4 times the original one.
The equilibrium condition allows finding the correct answer for the force that is resisting the weight of the apple is:
3. Normal force
Newton's second law gives the relationship between <em>force, mass</em> and acceleration of bodies, in the special case that the acceleration is is called the equilibrium condition.
∑ F = 0
Where F is the external force.
The free body diagram is a diagram of the forces on bodies without the details of the shape of the body, in the attached we can see a scheme of the forces.
Let's write the equilibrium condition for the apple
N - W = 0
N = W
.
We can see that the only forces acting on the apple are its weights and reaction from the table called Normal.
Let's analyze the different answers:
1. False. The apple is not moving therefore the resistance is zero
2. False. The apple is not moving so friction it with the table is
3. True. The free-body diagram shows that the normal and the weight are equal
4. False. There is nothing to pull the apple so there is no tension
5. False. Gravity is the weight of the apple that is applied to the table, not from the table to the apple.
In conclusion using the equilibrium condition we can find the correct result for the force that is resisting the weight of the apple is:
3. Normal force
Learn more here: brainly.com/question/2872207
