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2 years ago

In the picture below, explain why the bear fell. Use FRICTION to explain your answer.

1 answer:

algol132 years ago

5 0

The bear fell because it slides to the surface of ice due to lack of friction.

One of these theories is that friction causes the liquid layer of water to form on ice. Friction is the force that generates heat whenever two objects slide against each other. If you rub your hands together, you can feel them heat up. That's friction at work. When a skate moves over the surface of ice, the friction between the skate and the ice generates heat that melts the outermost layer of ice.

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If this energy were used to vaporize water at 100.0 ∘C, how much water (in liters) could be vaporized? The enthalpy of vaporizat

Zanzabum

Answer:

0.429 L of water

Explanation:

First to all, you are not putting the value of the energy given to vaporize water, so, to explain better this problem, I will assume a value of energy that I took in a similar exercise before, which is 970 kJ.

Now, assuming that the water density is 1 g/mL, this is the same as saying that 1 g of water = 1 mL of water

If this is true, then, we can assume that 1 kg of water = 1 L of water.

Knowing this, we have to use the expression to get energy which is:

Q = m * ΔH

Solving for m:

m = Q / ΔH

Now "m" is the mass, but in this case, the mass of water is the same as the volume, so it's not neccesary to do a unit conversion.

Before we begin with the calculation, we need to put the enthalpy of vaporization in the correct units, which would be in grams. To do that, we need the molar mass of water:

MM = 18 g/mol

The enthalpy in mass:

ΔH = 40.7 kJ/mol / 18 g/mol = 2.261 kJ/g

Finally, solving for m:

m = 970 / 2.261 = 429 g

Converting this into volume:

429 g = 429 mL

429 / 1000 = 0.429 L of water

3 0

2 years ago

A 29 cm pencil is placed 35cm in front of a convex lens and is illuminated by a spotlight. the focal point of the lens is 28cm f

vovikov84 [41]

A) What is the height of the pencil image

4 0

2 years ago

lidiya [134]

Answer:

ma= ma

m⋅a = m⋅a

And equivalently:

am=ma

a⋅m = m⋅a

Explanation:

Question

Assuming this question "Similar to what you see in your textbook, you can generally omit the multiplication symbol as you answer questions online, except when the symbol is needed to make your meaning clear. For example, 1*10^5 is not the same as 110^5 . When you need to be explicit, type * (Shift + 8) to insert the multiplication operator. You will see a multiplication dot (⋅) appear in the answer box. Do not use the symbol x. For example, for the expression ma,

typing m⋅a would be correct, but mxa would be incorrect".

Solution to the problem

For this case we want to write a expression for ma, and based on the previous info we can write:

ma= ma

m⋅a = m⋅a

And equivalently:

am=ma

a⋅m = m⋅a

But is not correct do this:

mxa=mxa

axm = mxa

8 0

2 years ago

Read 2 more answers

The operator of a space station observes a space vehicle approaching at a constant speed v. The operator sends a light signal at

GenaCL600 [577]

Answer:

The speed of the light signal as viewed from the observer is c.

Explanation:

Recall the basic postulate of the theory of relativity that the speed of light is the same in ALL inertial frames. Based on this, the speed of light is independent of the motion of the observer.

5 0

2 years ago

A 26 cm object is 18 cm in front of a plane mirror. A ray of light strikes the object and is reflected off the mirror at a 42-de

matrenka [14]

Answer:

42 degrees, virtual image, same size as the object (26 cm)

Explanation:

The law of reflection states that:

- When a ray of light is incident on a flat surface (such as the plane mirror), the angle of reflection is equal to the angle of incidence

So, since in this case the angle of incidence is 42 degrees, the angle of reflection is also 42 degrees.

Moreover, the image formed by a plane mirror is always:

- Virtual (on the same side as the object)

- The same size as the object

So in this case, since the object's size is 26 cm, the image's size is also 26 cm.

8 0

2 years ago