Think of an experiment you did in a past science class. a. Describe the experiment. b. What was the experimental variable? c. What were two control variables? d. What was the outcome of the experiment?

In an experiment, the experimental treatment differs from the control treatment only in the ___ being studied. a. experiment b. variable c. hypothesis d. data

Scientists believe that Earth once had naturally existing plutonium-$239$. Suppose Earth had $10$ trillion tons of Pu-$239$ when it formed. Given plutonium's half-life of $24,000$ years and Earth's current age of $4.6$ billion years, how much would remain today? Use your answer to explain why plutonium is not found naturally on Earth today.

Red light emitted by hydrogen atoms at rest in the laboratory has wavelength 656 nm. Light emitted in the same process on a distant galaxy is received at Earth with wavelength $708 \mathrm{~nm}$. Describe the galaxy's motion relative to Earth.

A muon formed high in Earth’s atmosphere travels toward Earth at a speed v = 0.990c for a distance of 4.60 km as measured by an observer at rest with respect to Earth. It then decays into an electron, a neutrino, and an antineutrino. A third observer traveling toward the muon at c/2 measures the lifetime of the particle. According to this observer, is the muon’s lifetime shorter or longer than the lifetime measured by the observer at rest with respect to Earth? Explain.

Use the internet to conduct additional research on the effects of social class on socialization. Collect evidence from recent studies. Then write an essay of at least two pages in which you summarize the studies and draw conclusions about how and why socialization processes vary by social class.

A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at 22"" with the horizontal. The horizontal component of the earth at the place is known to be $0.35 \mathrm{G}$. Determine the magnitude of the earth

Analyze the Earth-Sun system by following the Bohr model, where the gravitational force between Earth (mass $m$ ) and Sun (mass $M$ ) replaces the Coulomb force between the electron and proton (so that $F=$ $G M m / r^2$ and $P E=-G M m / r$. Show that (d) Using the Earth-Sun orbit radius of $r=1.49 \times 10^{11} \mathrm{~m}$, determine the value of the quan- tum number $n$.

Assume a hole is drilled through the center of the Earth. I drop a small mass into this hole and after some time find it emerging on the opposite side of the Earth. The mass then falls back in again and continues to oscillate. Find the period of this oscillation. Clearly state any assumptions made. If the diameter of the hole were a significant fraction of the size of the Earth would this affect your answer? If so, how?

The Museum of Health and Medical Science in Houston,Texas, has one of the largest kaleidoscopes in the world. It is a cylinder 10 feet long and 22 inches in diameter. What is the surface area of the kaleidoscope?

A spaceship leaves Earth traveling at $0.66 c$. A second spaceship leaves the first at a speed of $0.87 c$ with respect to the first. Calculate the speed of the second ship with respect to Earth if it is fired in the same direction the first spaceship is already moving.

Sarah, David, and Ali are friends in science class. The teacher randomly chooses two of the 12 students in the class to work together on a project. What is the probability that two of these three friends will be chosen?

At the surface of a certain planet, the gravitational acceleration $g$ has a magnitude of $12.0$ m/s$^2$. A $2.10$-kg brass ball is transported to this planet. What is (a) the mass of the brass ball on the Earth and on the planet, and (b) the weight of the brass ball on the Earth and on the planet?

Suppose a planet is discovered that has the same amount of mass in a given volume as the Earth, but has half its radius. Is the acceleration due to gravity on this planet more than, less than, or the same as the acceleration due to gravity on the Earth? Explain.