Describe some of the things Darwin saw that caused him to hypothesize that species evolve.

A forage that grows in wet or poorly drained soil is
a. reed canary grass.
b. timothy.
c. fescue.
d. bird's-foot trefoil.

Janet remembered only a few of the innumerable faces she saw during...

Categorize the following objects as conductors or insulators: a. copper wire b. your body when your skin is wet c. a plastic comb

Verify that $A \sin (k x)+B \cos (k x)$ is a solution of equation we saw earlier.

A clothesline is stretched taut between two poles. Then a wet towel is hung at the center of the line. Can the line remain horizontal? Explain.

A contracting company rents a generator for 6 hours and a heavy-duty saw for 6 hours at a total cost of 48 dollars. For another job the company rents the generator for 4 hours and the saw for 8 hours for a total cost of 40 dollars. Find the hourly rates $g$ (for the generator) and $s$ (for the saw) by solving the system of equations $6 g+6 s=48$ and $4 g+8 s=40$.

Place a check beside each sentence in which the pronoun and antecedent are in agreement. _____ Enough of the cake mix had gotten wet to make it unusable.

A father (mass $M$ ) and his son (mass $m$ ) begin walking out toward opposite ends of a balanced see-saw. As they walk, the see-saw stays exactly horizontal. What can be said about the relationship between the father's speed $V$ and the son's speed $v$?

What is the product of the uncernainties determined in Exercises we saw earlier? Discuss the result.

A car is sitting outside in a driveway. Consider the following statement, "If it starts raining, the car will get wet."

a. Is the converse of the statement true? Explain.

A soybean farmer finds that the older leaves of his plant are turning yellow following a long period of wet weather. Suggest a reason why.

A potter’s wheel having a radius of 0.50 m and a moment of inertia of 12 $k g \cdot m ^ { 2 }$ is rotating freely at 50 rev/min. The potter can stop the wheel in 6.0 s by pressing a wet rag against the rim and exerting a radially inward force of 70 N. Find the effective coefficient of kinetic friction between the wheel and the wet rag.

Wet atmospheric air at 100 percent relative humidity contains saturated water vapor and, by Dalton’s law of partial pressures,

$$P_{atm} = P_{dry air} + P_{water vapor}$$

Suppose this wet atmosphere is at 40°C and 1 atm. Calculate the density of this 100 percent humid air, and compare it with the density of dry air at the same conditions.