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3 years ago

A pot of water at 20.0ºC is warmed to 100º when 40000cal is added. what is the mass of the water?

Physics

1 answer:

mario62 [17]3 years ago

4 0

Answer:

500 g

Explanation:

m = Mass of water

c = Specific heat of water = $1\ \text{cal/g}^{\circ}\text{C}$

$\Delta T$ = Temperature difference = $100-20=80^{\circ}\text{C}$

Q = Heat added = 40000 cal

Heat is given by

$Q=mc\Delta T\\\Rightarrow m=\dfrac{Q}{c\Delta T}\\\Rightarrow m=\dfrac{40000}{1\times 80}\\\Rightarrow m=500\ \text{g}$

The mass of water is 500 g.

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Why caring a body and moving with it is not a work done<br><br> Why :

Alecsey [184]

Answer:

Work done on an object is equal to

FDcos(angle).

So, naturally, if you lift a book from the floor on top of the table you do work on it since you are applying a force through a distance.

However, I often see the example of carrying a book through a horizontal distance is not work. The reasoning given is this: The force you apply is in the vertical distance, countering gravity and thus not in the direction of motion.

But surely you must be applying a force (and thus work) in the horizontal direction as the book would stop due to air friction if not for your fingers?

Is applying a force through a distance only work if causes an acceleration? That wouldn't make sense in my mind. If you are dragging a sled through snow, you are still doing work on it, since the force is in the direction of motion. This goes even if velocity is constant due to friction.

Explanation:

8 0

2 years ago

When a liquid is cooled, the kinetic energy of the particles ?

vodka [1.7K]

When a liquid is cooled, the kinetic energy of the particles, DECREASES..

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2 years ago

How high was a brick dropped from if if falls in 2.5 seconds?

jenyasd209 [6]

Using the kinematic equation d = V_0 * t + 1/2 * a * t^2, where d is height you can rewrite this to be d = 1/2*g*t^2 or 4.9t^2
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2 years ago

A bicycle pump contains 20 cm3 of air at a pressure of 100 kPa. The air is then pumped in a tyre of volume 100 cm3. Calculate th

Natasha2012 [34]

Answer:

The pressure of the air in the tyre is 20 kPa

Explanation:

The parameters for the bicycle pump and tyre are;

The volume of air contained in the bicycle pump, V₁ = 20 cm³

The pressure of the air contained in the bicycle pump, P₁ = 100 kPa

The volume (available) of the tyre, where the air is pumped, V₂ = 100 cm³

Let P₂ represent the pressure in the tyre after the air is pumped

By Boyle's law, we have that at constant temperature, the volume of a given mass of gas is inversely proportional to its pressure;

Mathematically, Boyle's law gives the following equation;

P₁ × V₁ = P₂ × V₂

∴ P₂ = (P₁ × V₁)/V₂

Substituting the known values gives;

P₂ = (100 kPa × 20 cm³)/(100 cm³)

∴ P₂ = 100 kPa × 1/5 = 20 kPa

P₂ = 20 kPa

The pressure of the air in the tyre = P₂ = 20 kPa.

7 0

2 years ago

observe the figure given carefully volume of water in each vessel is shown arrange them in order of decreasing pressure at the b

mihalych1998 [28]

Answer:

See the explanation below

Explanation:

The pressure is defined as the product of the density of the liquid by the gravitational acceleration by the height, and can be easily calculated by means of the following equation.

$P=Ro*g*h$

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Ro = density of the fluid [kg/m³]

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h = elevation [m]

In this way we can understand that the greater pressure is achieved by means of the height of the liquid, that is, as long as the fluid has more height, greater pressure will be achieved at the bottom.

Therefore in order of decreasing will be

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The pressure decreases as we go from the container B - D - A - C

5 0

3 years ago