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romanna [79]
3 years ago
12

The latent heat of fusion of alcohol is 50 kcal/kg and its melting point is -54oC. It has a specific heat of 0.60 in its liquid

state. Calculate the energy needed to melt 2.0 kg of solid alcohol at -54o and raise it to a temperature of -4°C.
40. kcal
100 kcal
160 kcal
280 kcal
Physics
1 answer:
sashaice [31]3 years ago
5 0

Answer:

C

Explanation:

To melt the alcohol

Heat needed = M . L  = 2 . 25  = 50 kcal

To warm up the alcohol

Heat needed = M . sp. ht. . ∆t   = 2 . 0.6 . 100  = 120 kcal

Total heat needed = 170 kcal

Assuming that 0.6 kcal/ kg / ˚C  is the specific heat and that the answer is wanted in kcal ( a rather odd unit to be in use here.)

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max2010maxim [7]

Answer:

E. all of these

Explanation:

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all are necessary to designate a point in space. Hence option E is correct.

For example in simple harmonic motion we need to specify all the above factors of the object in order to designate the position of the object.  

8 0
3 years ago
An 1800 kg helicopter rises with an upward acceleration of 2.0 m/s?. What lifting force is supplied by its rotating blades?
Viktor [21]

Answer:

Lifting force, F = 21240 N

Explanation:

It is given that,

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It rises with an upward acceleration of 2 m/s². We need to find the lifting force  supplied by its rotating blades. It is given by :

F = mg + ma

Where

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and "ma" is an additional acceleration when it is moving upwards.

So, F=1800\ kg(9.8\ m/s^2+2\ m/s^2)

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4 0
3 years ago
jenny's model train is set up on a circular track. There are six telephone poles evenly spaced around the track. It takes the en
d1i1m1o1n [39]

Answer:

T = 60 s

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now we have time period of the train given as

T = \frac{2\pi}{\omega}

T = \frac{2\pi}{\frac{\pi}{30}}

T = 60 s

5 0
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7 0
3 years ago
Can you please summarise this, because I can't get the topic
wlad13 [49]
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