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3 years ago

13

In the figures below, there are four copper wires shown. Assuming that all the wires are the same temperature, which has the gre

atest resistance?

1 answer:

hichkok12 [17]3 years ago

8 0

The speed of the ball is how hard you hit it

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Calculate the average atomic mass of element, X. A sample of X is 65.20% X-17, 13.50% X-18, and 21.30% X-19.

k0ka [10]

Answer:

The average atomic mass of element X is 17.561 u.

Explanation:

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

We are given:

Mass of isotope X-17 = 17 u

Percentage abundance of isotope X-17 = 65.20 %

Fractional abundance of isotope 1 = 0.6520

Mass of isotope X-18 = 18 u

Percentage abundance of isotope X-18 = 13.50 %

Fractional abundance of isotope X-18 = 0.1350

Mass of isotope X-19 = 19 u

Percentage abundance of isotope X-19 =21.30%

Fractional abundance of isotope X-19 = 0.2130

Putting values in equation 1, we get:

$\text{Average atomic mass of Z}=\sum[(17 u\times0.6520 )+(18 u\times 0.1350)+(19 u\times 0.2130)]$

$\text{Average atomic mass of Z}=17.561 u$

6 0

3 years ago

Hydrogen fuel cells are used on the space shuttle to provide the shuttle with all of its electrical energy. Explain why fuel cel

UkoKoshka [18]

Answer:

Hydrogen used in fuel cells has the energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, similarly to gasoline vehicles.

5 0

3 years ago

By how many newtons does the weight of a 85.9-kg person lose when he goes from sea level to an altitude of 6.33 km if we neglect

sergejj [24]

Answer:

$Weight\ loss=1.6321N$

Explanation:

From the question we are told that:

Weight $W=85.9kg$

Altitude $h= 6.33 km$

Let

Radius of Earth $r=6380km$

Gravity $g=9.8m/s^2$

Generally the equation for Gravity at altitude is mathematically given by

$g_s=9.8(\frac{6380}{6380+6.33})^2$

$g_s=9.781m/s^2$

Therefore

Weight at sea level

$W_s=9.8*85.9$

$W_s=841.82N$

Weight at 6.33 altitude

$W_a=9.781*85.9$

$W_a=840.2N$

Therefore

$Weight loss=W_s-W_b$

$Weight loss=841.82-840.2$

$Weight loss=1.6321N$

3 0

3 years ago

An underground tunnel has two openings, with one opening a few meters higher than the other. If air moves past the higher openin

klasskru [66]

Answer:

There would be a pressure drop in the direction of the higher opening. This will force air to move in from the lower opening and force it to leave through the higher opening. This will create a convectional movement of air, cooling and ventilating the tunnel.

Explanation:

This is in accordance with bernoulli's law of fluid flow which states that the pressure exerted by a moving fluid is lesser than it would exert if it were at rest.

6 0

3 years ago

An internal combustion engine uses fuel, of energy content 44.4 MJ/kg, at a rate of 5 kg/h. If the efficiency is 28%, determine

Fudgin [204]

Efficiency = Power Output / Power Input

Power Input = Rate of Energy input = 44.4 MJ/kg * 5 kg/h

= 222 MJ/h

But 1 hour = 3600seconds

222 MJ/h = 222 MJ/3600s = 0.061667 MW J/s = Watts

Power input = 0.061667 MW = 61 667 W

From Efficiency = Power Output / Power Input

   28% = Power Output / 61667

   Power Output = 0.28 * 61667

   Power Output = 17266.76 W

Power Output = 17 267 W

Rate of heat Rejection = Power input - Power output

      = 61667 - 17267 = 44400 W

Rate of heat Rejection = 44 400 W.

C- Copyright.

5 0

3 years ago