To solve this question, you need to know the definition of density:

The question gives us the mass of the block and the density of the block. We can use these values to solve for the volume of the block.

Density has to be converted fromto(SI units). Recall that; therefore,.

Solving for volume of the block gives us:

A liter is defined as; therefore,.

Remember that the volume of a cube is calculated as follows:

从多维数据集具有相同的长度,宽度,和黑ght, the equation above can be rewritten in terms of height as follows:

This means that the height of the cube can be calculated by taking the cube root of volume:

The length, the width, and the height of this cubical block is.

Density is defined as mass divided by volume. Recall that the solid phase is usually characterized by tightly packed molecules. As a result, solids usually take up less volume than liquids and, consequently, have greater densities than liquids.

The most common exception to this rule is water. Liquid water has a density of, whereas solid water (ice) has a density of.

Density of any substance (solid or liquid) is calculated as follows:

is density of the substance,is mass, andis volume. The density of a substance does not depend on the weight of the object.

Changing a substance from its solid phase to its liquid phase only alters volume; it does not change the mass. Remember that the mass of a substance depends on the amount of molecules. Changing from solid to liquid will increase the spacing between the molecules (volume), but it will not change the amount of molecules (mass); therefore, the solid phase and the liquid phase of a sample of substance will have the same mass.

Increasing a substance’s temperature to its melting point will convert the substance from a solid to a liquid. This will increase the volume of the substance because the molecules within the substance will be farther apart from each other; however, the amount of molecules (mass of the substance) will remain unchanged.

Recall the definition of density:

Since the volume increases and the mass stays the same, the density of iron will decrease when you change the temperature to its melting point.

Density is defined as follows:

To alter density, we need to alter mass and/or volume. Remember that mass can only be altered by removing from or adding to the sample. Temperature and pressure do not change the amount of substance; therefore, they do not alter the mass of the substance.

Changing temperature will alter the distance between the molecules within the substance. Increasing the temperature will increase the distance between the molecules, which will increase the volume taken up by the substance. Similarly, decreasing the temperature will decrease the distance between the molecules, which will decrease the volume taken up by the substance. This means that changing temperature will alter the volume of the substance and, subsequently, the density of the substance.

Applying pressure also changes the distance between the molecules. Increasing the pressure will force the molecules to be closer together, whereas decreasing the pressure will enable the molecules to spread and separate from each other; therefore, pressure also alters density by changing the volume of the substance.

To answer this question, you need to solve for the stress experienced by the tube. Stress is defined as:

Since this is a tube, the area we are concerned with is the circular cross-sectional area of the tube. The question states that the diameter is. This means that the radius (which is half the length of the diameter) is. Recall that meters is the SI unit for distance; therefore, we need to convert the radius to meters:

This means that the radius of the tube, in meters, is. The area of a circle is:

Using this formula and our radius, we can find the cross-sectional area:

The stress experienced by the tube is:

The closest answer choice is.

The question states that the tube is being stretched by the force. This means that the tube is undergoing tension because you are pulling the tube and applying a force outwards. If the force was applied in the opposite direction (inwards), then the tube would be undergoing compression (the tube would shorten).

Strain of an object is defined as:

is the final length andis the initial length. The equation implies that increasing the initial length of an object () would decrease the strain. Similarly, the equation also implies that increasing the final length of an object () would increase the strain; therefore, increasing the initial length decreases strain, whereas increasing the final length increases strain.

To answer this question, we need to know the equation for Young’s modulus,:

Recall the definitions of stress and strain:

Here,is force,is cross-sectional area,is change in length, andis initial length. Plugging these two equations into the definition of Young’s modulus gives us:

Rearranging this equation to solve for change in length gives us:

因为我们want to increasewe look for answer choices that increaseand, or decreaseand. Among the answer choices, the greatest increase occurs when you double the elasticity of the rubber band. Recall that Young’s modulus is a measure of the stiffness of a material; therefore, a more elastic (flexible, or less stiff) material will lower Young’s modulus. Having a material twice as elastic will decreaseby one half and will give the greatest increase in the change in length of the rubber band.

Using half the length () and using twice the cross-sectional area will decrease the change in length. Using a rubber band twice as long, but twice as elastic, will not alter the change in length.

杨氏modulus is a constant that is calculated by generating a stress vs. strain plot. The slope of the linear region of the stress vs. strain plot is defined as the Young’s modulus. Recall that the stress vs. strain plot is nonlinear past the elastic limit (stress at which the material starts to plastically deform). This means that we cannot calculate the slope past the elastic limit; Young’s modulus is invalid for stresses beyond the elastic limit.

杨氏modulus is defined as follows:

To calculate strain, you divide change in length by initial length. Since both change in length and initial length have the same units, the units cancel and strain becomes a dimensionless quantity. This means that the Young’s modulus will have the same units as stress alone.

杨氏modulus is a material property. This means that the Young’s modulus is constant for a given type of material. It does not depend on the stress experienced by the material. Any changes to stress will be compensated for by a change in strain, which will allow Young’s modulus to be constant for the material. Similarly, Young’s modulus does not depend on strain or on the geometrical properties (length and area) of the material. It will only change if you change the type of material being used.

As water freezes, it releases heat into the universe to balance the local loss of entropy encountered by ordering atoms into a rigid solid structure. Entropy, in contrast, is not a commodity that can be released by a reaction in the same way as heat. Also, water vapor would not be released on only one side of the equation. Water vapor would exist with in equilibrium with both solid and liquid, but would not appear as an additional product with the solid phase in this reaction.

The energy required to cause a liquid-gas phase change is called the heat of vaporization, and is usually given in the units of kilojoules per mole. Enthalpy of vaporization and heat of vaporization are the same quantity.

When the heat of vaporization is given for a single gram of substance, with the units of Joules per gram, it is termed the specific heat of vaporization. This is the quantity given in the question: the energy required to vaporize exactly one gram of the sample.

Specific heat capacity refers to the energy needed to raise the temperature of one gram of a sample by one degree Celsius.