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2 years ago

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An ocean liner leaves New York City and travels 18.0o north of east for 155 km. How far east and how far north has it gone? In o

ther words, what are the magnitudes of the components of the ship’s displacement vector in the north and the east direction, respectively?

1 answer:

Monica [59]2 years ago

6 0

I’m sorry if i took up a lot of space, hope this is a valid approximate answer

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Mature salmon swim upstream, returning to spawn at their birthplace. During the arduous trip they leap vertically upward over wa

patriot [66]

Answer:

The minimum speed is 7.5 m/s.

Explanation:

Given that,

Height = 2.87 m

We need to calculate the minimum speed

Using equation of motion

$v^2=u^2-2gh$

$u=\sqrt{2gh}$

Where, u = minimum velocity

g = acceleration due to gravity

h = height

Put the value into the formula

$u=\sqrt{2\times9.8\times2.87}$

$u=7.5\ m/s$

Hence, The minimum speed is 7.5 m/s.

5 0

4 years ago

Explain how polarization of a cell increases the cell's internal resistance.<br>(2<br>2.

Mandarinka [93]

Answer:

Explanation: The chemical action that occurs in the cell while the current is flowing causes hydrogen bubbles to form on the surface of the anode. This action is called POLARIZATION. Some hydrogen bubbles rise to the surface of the electrolyte and escape into the air, some remain on the surface of the anode. If enough bubbles remain around the anode, the bubbles form a barrier that increases internal resistance. When the internal resistance of the cell increases, the output current is decreased and the voltage of the cell also decreases.

A cell that is heavily polarized has no useful output. There are several methods to prevent polarization or to depolarize the cell.

One method uses a vent on the cell to permit the hydrogen to escape into the air. A disadvantage of this method is that hydrogen is not available to reform into the electrolyte during recharging. This problem is solved by adding water to the electrolyte, such as in an automobile battery. A second method is to use material that is rich in oxygen, such as manganese dioxide, which supplies free oxygen to combine with the hydrogen and form water.

A third method is to use a material that will absorb the hydrogen, such as calcium. The calcium releases hydrogen during the charging process. All three methods remove enough hydrogen so that the cell is practically free from polarization.

LOCAL ACTION

When the external circuit is removed, the current ceases to flow, and, theoretically, all chemical action within the cell stops. However, commercial zinc contains many impurities, such as iron, carbon, lead, and arsenic. These impurities form many small electrical cells within the zinc electrode in which current flows between the zinc and its impurities. Thus, the chemical action continues even though the cell itself is not connected to a load.

Local action may be prevented by using pure zinc (which is not practical), by coating the zinc with mercury, or by adding a small percentage of mercury to the zinc during the manufacturing process. The treatment of the zinc with mercury is called amalgamating (mixing) the zinc. Since mercury is many times heavier than an equal volume of water, small particles of impurities weighing less than mercury will float to the surface of the mercury. The removal of these impurities from the zinc prevents local action. The mercury is not readily acted upon by the acid. When the cell is delivering current to a load, the mercury continues to act on the impurities in the zinc. This causes the impurities to leave the surface of the zinc electrode and float to the surface of the mercury. This process greatly increases the storage life of the cell.

6 0

3 years ago

If 500g of water at 20 degrees C is mixed with 750g of water at 30 degrees C, what will the temperature of the mixture be?

hjlf

Answer:

$26 ^\circ C$

Explanation:

Given that the temperature of $500g$ of water and $750 g$ of water are

at $20^{\circ}C$ and $30^\circ C$ respectively.

Let $m_1=500g$ , $T_1= 20^\circ C$

and $m_2=750g$ , $T_2= 30^\circC$ .

The specific heat capacity of water is,

$C= 4.186 J/g ^\circ C$ .

Let the final temperature of the mixture be $T^\circ C$ .

As there is no energy loss, so, the energy loss by the water at higher temperature, i.e. $30^\circ C$ , will be equal to the energy gain by the water at lower temperature, i.e. $20^{\circ}C$ .

$m_2C (T_2-T)=m_1C(T-T_1)$

$\Rightarrow m_2 (T_2-T)=m_1(T-T_1)$ [ both sides divided by $C$ ]

$\Rightarrow m_2T_2-m_2T=m_1T-m_1T_1$

$\Rightarrow m_1T+m_2T=m_1T_1+m_2T_2$

$\Rightarrow T=\frac{m_1T_1+m_2T_2}{m_1+m_2}$

Now, putting the given value in the above equation, we have

$\Rightarrow T=\frac {500\times 20+750\times 30}{500+750}$

$\Rightarrow T=26^\circ C.$

Hence, the temperature of the mixture will be $26 ^\circ C$ .

5 0

3 years ago

A standard door into a house rotates about a vertical axis through one side, as defined by the door's hinges. A uniform magnetic

melomori [17]

Answer:

75.5degrees

Explanation:

Magnitude of magnetic flux= BA

If rotated through an angle= BAcos theta

= (0.25)BA=BAcos theta

= costheta= 0.25

= theta= cos^-1 0.25

=75.5degrees

4 0

3 years ago

Una rueda que tiene 15 cm de radio, realiza 64 vueltas en 16 seg. Calcula: Periodo Frecuencia Velocidad angular Velocidad lineal

liraira [26]

Answer:

i) El período de la rueda es de 0,25 segundos.

ii) La frecuencia de la rueda es 4 Hertz

iii) La velocidad angular es aproximadamente 25.133

iv) La velocidad lineal es de aproximadamente 3,77 m / s

Explanation:

El radio de la rueda, r = 15 cm = 0,15 m

El número de vueltas que hace la rueda = 64 vueltas

El tiempo que tarda el volante en dar 64 vueltas = 16 segundos

i) El período = El tiempo que tarda la rueda en dar 1 vuelta

∴ El período de la rueda, T = 16 segundos/(64 vueltas) = 0,25 segundos

El período de la rueda, T = 0,25 segundos

ii) La frecuencia = El número de vueltas por segundo

∴ La frecuencia de la rueda, f = 64 vueltas /(16 segundos) = 4 Hertz

1 vuelta = 2 · π radianes

La frecuencia de la rueda, f = 4 Hertz

iii) Velocidad angular = La medida del ángulo girado por segundo

∴ La velocidad angular, ω = 64 × 2 × π/16 segundos ≈ 8 · π rad/segundos ≈ 25.133 rad/seg

La velocidad angular, ω ≈ 25.133

iv) La velocidad lineal, v = r × ω

∴ v = 0,15 m × 8 · π rad / segundos ≈ 3,77 m/s

La velocidad lineal, v ≈ 3.77 m/s

7 0

3 years ago