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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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fomenos

Answer:

The bulbs should be connected in parallel.

Explanation:

We want to find out a way to hook  up 2 light bulbs and a battery so that when one bulb burns out or is disconnected the other bulbs stays lit.

We must connect the two bulbs in parallel so that even when one bulb is burns out, it will have no effect on the other bulb and the 2nd bulb will keep on working. The current flowing in each bulb will depend upon the resistance of each bulb and the voltage will be same across each bulb.

On the other hand, if we use a series circuit then if one bulb burns out then the there is no flow of current in the circuit and therefore, the second bulb will not be operational.

The current flowing through each bulb is given by

I = V/R

The voltage across each bulb is given by

V = IReq

Where I is the current and Req is the equivalent resistance of the two bulbs connected in parallel and is given by

Req = (R₁*R₂)/(R₁+R₂)

The connection diagram is attached where two bulbs are connected in parallel and are power with a battery.

4 0
3 years ago
You exert a 100-N force on a pulley system to lift 300-N. What is the mechanical advantage of this system? How many sections of
Andrei [34K]

Answer:

Mechanical advantage = 3

Explanation:

You exert a 100-N force on a pulley system to lift 300-N.

The mechanical advantage of the system is given by the ratio of output force to the input force.

Here, output force = 300 N and input force = 100 N

Mechanical advantage,

m=\dfrac{300}{100}\\\\m=3

Mechanical advantage is 3 it means that there are 3 sections of rope support. Hence, this is the required solution.

8 0
2 years ago
What is the displacement of the car between t=1s and t=4s
tensa zangetsu [6.8K]

Answer:

Option C. 30 m

Explanation:

From the graph given in the question above,

At t = 1 s,

The displacement of the car is 10 m

At t = 4 s

The displacement of the car is 40 m

Thus, we can simply calculate the displacement of the car between t = 1 and t = 4 by calculating the difference in the displacement at the various time. This is illustrated below:

Displacement at t = 1 s (d1) = 10 m

Displacement at t= 4 s (d2) = 40

Displacement between t = 1 and t = 4 (ΔD) =?

ΔD = d2 – d1

ΔD = 40 – 10

ΔD = 30 m.

Therefore, the displacement of the car between t = 1 and t = 4 is 30 m.

4 0
3 years ago
9. What is the acceleration of a boat if it starts from rest and then reaches a velocity of 24 m/s in 6.0 s?
Tom [10]

Answer:

b. 4 ms-2

Explanation:

acceleration = velocity / time

4 0
2 years ago
Educación física como se puede mejorar la técnica deportiva
motikmotik

Answer:

Varíe sus entrenamientos. Para muchos atletas, los ejercicios funcionales son el nombre del juego. ...

Realice un seguimiento y mida su rendimiento durante el entrenamiento. ...

Haga de la hidratación adecuada una prioridad. ...

Dedique suficiente tiempo a la recuperación. ...

Entrena tu cerebro. ...

Alimente su cuerpo de la manera correcta. ...

Considere agregar algunos suplementos a su dieta.

Explanation:

8 0
2 years ago
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