U (a) What is surface tension? Explain the phenomenon in terms of intermolecular
forces.
(b) Describe a simple experiment to demonstrate
the surface tension of a liquid.
(c) State three examples to illustrate the effects
of surface tension.
(d) Why does water wet a clean glass surface
whereas mercury does not?
(e) State two methods by which the surface
tension of a liquid may be reduced.
(SSCE)

Which lists the main components of darwin’s theory of evolution? a. random mutations drive evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms do not change. b. natural selection drives evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms change over time. c. natural selection drives evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms change over time. d. random mutations drive evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms do not change.

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

On a mild saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23degreesc. at noon the furnace is turned off, and the people go home. the temperature outside is a constant 16degreesc for the rest of the afternoon. if the time constant for the building is 3 hr, when will the temperature inside the building reach 18degreesc? if some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18degreesc?