Amy counts the wave crests traveling down a stretched string. five wave crests pass amy in two seconds. what is the frequency of the wave?
a. 5.0 hz
b. 2.5 hz
c. 10 hz
d. 2.0 hz

Ineed asap! list 3 examples in which friction us or makes things easier in our daily life. explain the effect of friction for each. *make sure you explain the effect of friction for each example! *

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Most of the volume of an atom is occupied by the