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3 years ago

3. When a person is outside of the system and they add energy to the

Physics

1 answer:

NISA [10]3 years ago

5 0

Answer:

We show added energy to a system as +Q or -W

Explanation:

The first law of thermodynamics states that, in an isolated system, energy can neither be created nor be destroyed;

Energy is added to the internal energy of a system as either work energy or heat energy as follows;

ΔU = Q - W

Therefore, when energy is added as heat energy to a system, we show the energy as positive Q (+Q), when energy is added to the system in the form of work, we show the energy as minus W (-W).

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Which energy source contributes least to global warming?

Nady [450]

It’s C
solar

correct me if i’m wrong though

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3 years ago

Which of the following statements is true?

Alborosie

My guess is A. I'm not 100% positive but i'm pretty sure.

8 0

3 years ago

2.5 g of helium at an initial temperature of 300 K interacts thermally with 9.0 g of oxygen at an initial temperature of 620 K .

muminat

Answer:

Explanation:

2.5 g of He = 2.5 / 4 mole

= .625 moles

9 g of oxygen = 9/32

= .28 mole of oxygen

C_p of He = 3/2 R

C_p of O₂ = 5/2 R

A ) Initial thermal energy of He = 3/2 n R T

= 1.5 x .625 x 8.32 x 300

= 2340 J

Initial thermal energy of O₂ = 5/2 n R T

= 2.5 x .28 x 8.32 x 620

= 3610.88 J

B ) If T be the equilibrium temperature after mixing

gain of heat by helium

= n C_p Δ T

= .625 x 3/2 R x ( T - 300 )

Loss of heat by oxygen

n C_p Δ T

= .28 x 5/2 R x ( 620 - T )

Loss of heat = gain of heat

.625 x 3/2 R x ( T - 300 ) = .28 x 5/2 R x ( 620 - T )

1.875 T- 562.5 = 868- 1.4 T

3.275 T = 1430,5

T = 436.8 K

Thermal energy of He

= 1.5 x .625 x 8.32 x 436.8

= 3407 J

thermal energy of O₂

= 2.5 x .28 x 8.32 x 436.8

= 2543.92 J

C )

Heat energy transferred

= .28 x 5/2 R x ( 620 - T )

= .28 x 5/2 x 8.32 x ( 620 - 436.8 )

1066.95 J

Heat will flow from O₂ to He

Final temperature is 436.8 K

7 0

3 years ago

Two birds have the same mass but one has bigger feet. How would pressure that they produce on the ground be different ?

Mama L [17]

Answer:

the pressure per square inch is greater from the smaller feet.

Explanation:

different weight distribution

3 0

3 years ago

Since vectors always have positive magnitudes, the sum of two vectors must have a magnitude greater than the magnitude of either

Natasha2012 [34]

Answer:

False.

Explanation:

Yes the magnitude of a vector is always positive , but a vector consists of

magnitude

direction

when two vectors are added their direction may be opposite to each other For example-

$a=3i+3j$

$b=3i-6j$ ,

then their resultant

$r=b+a\\r=3i+3j+3i-6j\\r=6i-3j$

This resultant vector's x and y component equal to y and x component of vector b so its magnitude will be equal to magnitude of vector b.

Therefore, the resultant magnitude not necessary equal to the magnitude of either vector.

6 0

3 years ago