Time (y) 15
1-
15 During a lab investigation, students added four 50 g masses to two boxes and arranged
the boxes so that they were motionless on a pulley, as shown in the diagram. The
students then followed the procedure described in the box. The students recorded their
observations after each procedure and reset the pulley system to the original conditions.
During which procedures did students observe an unbalanced upward force on Box 1?
1
Choose only one.
Procedures
A. Procedures only
B. Procedures 1, 2, and 3
50 g
mass
1. Push Box 1 downward. Observe. Reset.
2. Add another mass to Box 1. Observe. Reset.
3. Remove one mass from Box 2. Observe. Reset.
4. Add another-mass to Box 2. Observe. Reset.
5. Remove two masses from Box 1. Observe. Reset.
C. Procedures 4 and 5
Box 1
D. Procedures 3 and 4
E. Procedures 1, 3, and 5
Box 2

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.