Two bodies A and B are connected by a string over a pulley and a disc slides over the string (see the figure). Then (B+D) cannot be treated as a system. The reason is[ ]
a) The distance covered by B and D are equal
b) The distance covered by B and D are not equal
c) The directions of B and D are same
d) The directions of B and D are not same

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.

Increasing the pressure on one spot of a fluid will increase the pressure everywhere else in the fluid a. pascals principal b. archimedes' principal c. bernoulli's principal

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?