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2 years ago

Which would show an example of how physical changes are reversible?

Physics

2 answers:

kondor19780726 [428]2 years ago

8 0

Answer:

Melting tin and then cooling it into a mold

Explanation:

When you melt something, and when it cools it returns to its physical state, therefore the physical changes are reversible. For example, take chocolate. When chocolate melts its liquid, then when it's in a colder situation it becomes solid again and so on, the changes are reversible.

il63 [147K]2 years ago

8 0

Answer:

Explanation:

the physical change was the gold bar being cut and if it is put back together the physical change is reversed

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Heat in the amount of 100 kJ is transferred directly from a hot reservoir at 1320 K to a cold reservoir at 600 K. Calculate the

Zinaida [17]

Answer:0.0909 kJ/K

Explanation:

Given

Temperature of hot Reservoir $T_h=1320 K$

Temperature of cold Reservoir $T_l=600 K$

Heat of 100 kJ is transferred form hot reservoir to cold reservoir

Hot Reservoir is Rejecting heat therefore $Q_1=-100 kJ$

Heat is added to Reservoir therefore $Q_2=100 kJ$

Entropy change for system

$\Delta s=\frac{Q_1}{T_1}+\frac{Q_2}{T_2}$

$\Delta s=\frac{-100}{1320}+\frac{100}{600}$

$\Delta s=-0.0757+0.1666=0.0909 kJ/K$

As entropy change is Positive therefore entropy Principle is satisfied

4 0

2 years ago

Why does Earth's moon have no atmosphere?

Margaret [11]

You can eliminate the answer A because the moon is super cold
For answer B, atmosphere is contained of gasses, not just oxygen alone
Definitely not C
The answer is D because the moon's gravity isn't strong enough to hold the gasses, as a result, only a small amount of gasses has an attraction to it ( the moon has a little atmosphere though) but not enough to be considered

6 0

2 years ago

PLEASEEEE HELPPPPPPPPPPPP

lesantik [10]

Answer:

240 meter

Explanation:

d= s*d=60m/s * 4sec=240 meter

7 0

2 years ago

Astronaut Rob leaves Earth in a spaceship at a speed of 0.960c relative to an observer on Earth. Rob's destination is a star sys

olchik [2.2K]

Answer:

A) 15.0 years

Explanation:

Due to the distance to the star system is in light-year units, we can compute the time by using:

$t=\frac{d}{v}=\frac{14.4 l-y}{0.960}=15l-y$

then, Rob will take to complete the trip about 15 light-years.

hope this helps!!

7 0

2 years ago

The acceleration due to gravity on Jupiter is 2.5 times what it is here on earth. An object weighing 347.9 N here on earth will

inessss [21]

Answer: weight on Jupiter = 869.75 N

mass on Earth = mass on Jupiter = 35.5 Kg

Explanation:

W = mg

W = weight

m = mass

g = gravitational acceleration [ on the Earth, g₁ = 9,8 N/kg ]

On the Earth,

G₁ = m x g₁ = 347,9 N

On the Jupiter,

G₂ = mg₂

mass on the Earth = mass on the Jupiter !

m = G₁ : g = 347.9 N : 9,8 N/kg = 35.5 kg

G2 : G1 = 2.5

G₂ = 2,5 G₁ = 2,5 x 347.9 N = 869,75 N

5 0

2 years ago