Why do the densities of most substances decrease with an increase in temperature?

1 answer:

7 0

Because density is related to activity of particles, the higher the activity level (the faster they're moving, and distance between them) the less dense they are. for example, H2O in a solid the particles are close together with minimum movement and it exists as ice, but when heat is applied the particles become more active and move more decreasing the density becoming liquid water, then when excessive heat is applied the same occurs and it becomes gas steam

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Natasha_Volkova [10]

Answer:

h = height of the hotel room from the ground floor = 237.4m

Explanation:

Change in Potential Energy of tourist = ΔPE = PE2 – PE1 = mgh

PE1 is the potential energy of tourist at the ground floor

PE1 is the potential energy of tourist at the top (hotel room)

Given

PE1 = − 2.01 × 10⁵ J

PE2 = 0J

PE2 – PE1 = mgh

0 – (− 2.01 × 10⁵ J) = mgh

2.01 × 10⁵ J = 86.4×9.8×h

h = 2.01 × 10⁵/(86.4×9.8) = 237.4m

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3 years ago

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slava [35]

Answer:

11.9 minutes

Explanation:

The journey is 5000 meters long. The time it takes in seconds for the journey at this speed is 5000/7 =714 seconds.

714/60=time in minutes =11.9 minutes approximately.

6 0

3 years ago

A pump increases the pressure in the flow of water from 120 kPa to 400 kPa. The inlet and outlet diameters are 9 cm and 3 cm res

Alina [70]

Answer:

4.433 kW

Explanation:

Suppose the flow rate is the same at the inlet and outlet at 57 m3/hr.

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$\dot{V} = 57 / 3600 = 0.0158 m^3/s$

As we are neglecting loss from friction and elevations changed, the power delivered by the pump is the product of the change in pressure and the flow rate

$P = \Delta P \dot{V} = (400 - 120)*0.0158 = 4.433 kW$