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3 years ago

Which heavenly bodies are involved in causing the earths tides?

1 answer:

3 0

The answer is --> C. the earth, moon, and sun.

The gravitational pull of the moon and the sun creates tides on the earth.

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Metals in group 1 on the periodic table most commonly form which type of ion

givi [52]

Answer:

Group 1 - the alkali metals. The Group 1 elements in the periodic table are known as the alkali metals.

Explanation:

7 0

3 years ago

Determine the power that needs to besupplied by the fanifthe desired velocity is 0.05 m3/s and the cross-sectional area is 20 cm

Mariulka [41]

Answer:

A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.

Explanation:

Complete statement is: Determine the power that needs to besupplied by the fan if the desired velocity is 0.05 cubic meters per second and the cross-sectional area is 20 square centimeters.

From Thermodynamics and Fluid Mechanics we know that fans are devices that work at steady state which accelerate gases (i.e. air) with no changes in pressure. In this case, mechanical rotation energy is transformed into kinetic energy. If we include losses due to mechanical friction, the Principle of Energy Conservation presents the following equation:

$\eta\cdot \dot W = \dot K$

$\dot W = \frac{\dot K}{\eta}$ (Eq. 1)

Where:

$\eta$ - Efficiency of fan, dimensionless.

$\dot W$ - Electric power supplied fan, measured in watts.

$\dot K$ - Rate of change of kinetic energy of air in time, measured in watts.

From definition of kinetic energy, the equation above is now expanded:

$\dot W = \frac{\rho_{a}\cdot \dot V}{2\cdot \eta}\cdot \left(\frac{\dot V}{A_{s}} \right)^{2}$ (Eq. 2)

Where:

$\rho_{a}$ - Density of air, measured in kilograms per cubic meter.

$\dot V$ - Volume flow, measured in cubic meters per second.

$A_{s}$ - Cross-sectional area of fan, measured in square meters.

If we know that $\rho_{a} = 1.20\,\frac{kg}{m^{3}}$ , $\dot V = 0.05\,\frac{m^{3}}{s}$ , $\eta = 0.3$ and $A_{s} = 20\times 10^{-4}\,m^{2}$ , the power needed to be supplied by the fan is:

$\dot K = \left[\frac{\left(1.20\,\frac{kg}{m^{3}} \right)\cdot \left(0.05\,\frac{m^{3}}{s} \right)}{2\cdot (0.3)} \right]\cdot \left(\frac{0.05\,\frac{m^{3}}{s} }{20\times 10^{-4}\,m^{2}} \right)^{2}$

$\dot K = 62.5\,W$

A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.

5 0

3 years ago

A horizontal force of 100 N is required to push a 50 kg crate across a factory floor at a constant speed. What is the accelerati

luda_lava [24]

Answer:

a = 2m/s^2

Explanation:

Force (F) = 100 N

Mass (m) = 50 kg

Here,

F = m×a

100 = 50 × a

a = 100÷50

a = 2m/s^2

Thus, the acceleration on the cart is a = 2m/s^2

-TheUnknownScientist

6 0

3 years ago

_______ are different forms of a single element. A) Atoms B) Elements C) Ions D) Isotopes

ELEN [110]

The answer is D. Isotopes.
Hope that helped.

7 0

4 years ago

Read 2 more answers

HELP

Mila [183]

Answer: When you break on your bike and when you rub your hands together to get warm.

Explanation: Force and friction affect our daily lives in numerous amounts of ways. For instance, when a football is kicked, it moves faster later after some time its force decreases due to friction. A common example of friciton is when a bike stops. When the brakes are applied the friction on the pads cause the bike to stop. The rubbing hands is making friction. Which makes you get warm.

5 0

3 years ago