Distance (m)

What is the velocity of a car that went a distance of 400ft in 25 seconds

Rom4ik [11]

Answer:

I believe it is 1/6 M

Explanation:

sorry if i am not right but i think i am

3 0

3 years ago

Read 2 more answers

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Tema [17]

Answer:

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4 0

2 years ago

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Classify each process according to whether it does or does not produce a new substance.

AlexFokin [52]

The processes under chemical change are: cooking an egg, fireworks exploding, and rusting of a metal tool.

The processes under physical change are: melting ice, evaporating puddle of water, and dissolving of salt in water.

Given:

The following process:

cooking an egg
melting ice
fireworks exploding
evaporating puddle of water
rusting of a metal tool
Dissolving of salt in water

To find:

The classify the processes in whether it does or does not produce a new substance.

Solution:

Chemical change is the change when a new substance is formed due to a change in the chemical composition of the substance.
Physical change is the change in which no change in chemical composition takes place and the identity of the substance remains the same.

Cooking an egg

Chemical change, due to change in atomic arrangement egg get solidified on cooking, a new substance is formed.

Melting ice

Physical change, change in the state of matter is taking from solid to liquid, no new substance is formed.

Firework exploding

Chemical change. formation of carbon dioxide gas and sound energy, anew substance formed

Evaporating puddle of water

Physical change, change in the state of matter is taking from liquid to gas, no new substance is formed.

Rusting of metal tool

Chemical change, formation of oxides on the surface of the metal tool due to reaction between air and metal, a new substance is formed.

Dissolving of salt in water

Physical change, ions of salt in the solid state are changing into aqueous ions with no formation of new substance, no new substance is formed.

The processes under chemical change are: cooking an egg, fireworks exploding, and rusting of a metal tool.

The processes under physical change are: melting ice, evaporating puddle of water, and dissolving of salt in water.

Learn more about physical change and chemical change here:

brainly.com/question/864557?referrer=searchResults

brainly.com/question/13316655?referrer=searchResults

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: <em>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.</em>

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

Two people were pulling this thing with 560 Newton. Now they are using a rope with 50°. How much Newton would they need to pull

Brums [2.3K]

Answer:

10 N

Explanation:

While many people would like to simply add the forces from each end to get a total force, this is fundamentally incorrect.

MIGHT BE TOTALLY WRONG

4 0

3 years ago