Using the first law of thermodynamics, explain why the total energy of an isolated system is always constant.

A gas is enclosed in a container fitted with a piston of cross-sectional area 0.150 m$^2$. The pressure of the gas is maintained at 6 000 Pa as the piston moves inward 20.0 cm. Calculate the work done by the gas.

Perform the indicated operations. $(x + 2)(x + 3)$

Simplify.

$$3 x y x - 2 x y ^ { 2 } + y x ^ { 2 }$$

Clearly distinguish among temperature, heat, and internal energy.

When a person allows personal opinions, values, or tastes to influence a conclusion, that person is using ____ reasoning.

Evaluate each expression. P(8, 8)

What is the total charge in coulombs of 75.0 kg of electrons?

Compute the directional derivative of f at the given point in the direction of the indicated vector. f(x, y) defined by $2 x^{2} y-y z^{3}+x z^{2}-2 x^{2}=0$ (z>0), at (1, 1) in the direction of $\langle 3,-1\rangle$.

Find the average rate of change for the function over the given interval. $y=x^{2}+2 x$ between $x=1$ and $x=3$.

Find each probability for selecting a letter at random from the word ARKANSAS.

$$P ( \mathrm { K } \text { or } \mathrm { N } )$$

You are standing against the wall near a corner of a large building. A friend is standing against the wall that is around the corner from you. You can’t see your friend. How is it that you can hear her when she talks to you?

Name each quadrilateral parallelogram, rectangle, rhombus, or square - for which the statement is always true. The diagonals bisect opposite angles.

Gino has 5 blue socks and 4 black socks. He selects one sock at random. Without replacing the sock, he selects a second sock at random. Find each probability. P(blue, then blue)