Una niña está empujando un baúl. El PESO del baúl es de 230 N y el roce es de 50 N, la niña sólo logra ejercer una fuerza de 30
1 answer:
Answer:
Su padre necesita aplicar una fuerza de 20 newtons en la misma dirección que la fuerza aplicada por su hija.
Explanation:
Asúmase que el baúl se mueve en una superficie horizontal. La fuerza de rozamiento dada por el problema es la fuerza de rozamiento estático máximo, se requiere una fuerza externa antiparalela a la fuerza de rozamiento estático máximo para que el baúl se empiece a mover. La ecuación de equilibrio de fuerzas horizontales sobre el baúl es:
Donde:
- Fuerza externa aplicada sobre el baúl, medida en newtons.
- Fuerza de rozamiento estático máximo, medida en newtons.
Se despeja la fuerza externa:
Si , entonces:
Si la niña solo logra ejercer una fuerza de 30 newtons, su padre necesita aplicar una fuerza de 20 newtons paralela a aquella fuerza.
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Answer:
It would not be possible the cohesion among water molecules by the polar covalent bonding.
Well, to understand this in a better way, let's begin by explaining that water is special due to its properties, which makes this fluid useful for many purposes and for the existence of life.
In this sense, one of the main properties of water is cohesion (molecular cohesion), which is the attraction of molecules to others of the same type. So, water molecule () has 2 hydrogen atoms attached to 1 oxygen atom and can stick to itself through hydrogen bonds.
How is this possible?
By the polar covalent bonding, a process in which electrons are shared unequally between atoms, due to the unequal distribution of electrons between atoms of different elements. In other words: slightly positive and slightly negative charges appear in different parts of the molecule.
Now, it can be said that a water molecule has a negative side (oxygen) and a positive side (hydrogen). This is how the oxygen atom tends to monopolize more electrons and keeps them away from hydrogen. Thanks to this polarity, water molecules can stick together.
1) The equivalent resistance is
2) The voltage in the circuit is 120 V
3) The total current in the circuit is 44.0 A
Explanation:
1)
Resistors are said to be in parallel when they have the same potential difference at their terminals.
The formula to calculate the equivalent resistance for three resistors in parallel is:
where are the resistances of the three resistors.
In this problem, the resistance of each resistor is:
Substituting,
So the equivalent resistance is
2)
In this problem we are told that the three resistors are connected in parallel. This means that their terminals are connected to the same point of the circuit: therefore, this means that they also have the same potential difference across them.
Therefore, the voltage in each branch containing each resistor is the same, and it is equal to the voltage of the battery, which is
So, the voltage in the circuit is 120 V.
3)
The total current in the circuit can be found by using Ohm's law:
where
V is the voltage
R is the equivalent resistance of the circuit
I is the current
In this circuit, we have:
V = 120 V
Re-arranging the equation for I, we find the current:
Learn more about current and potential difference:
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