>> Civil Engineering
1.A mass on a spring has an acceleration given as follows: a= -10 (1/?sec?^2 ) x where x is the displacement of the mass in meters. If the initial position is -1 m and the initial velocity is +1 m/sec, find: (i) the velocity when x = 0 for the first time and (ii) the maximum and minimum values of x.
2.A stone A is dropped from rest down a well, and in 1 second another stone B is dropped from rest. Determine the distance between the stones another second later.
3.A 6.6 mA current is flowing through a 47 kilo-Ohm, 5% tolerance, 2-watt resistor. If the resistor values are uniformly distributed, how many resistors out of a package of 100 would you expect to burn up? At what value of resistances are you OK?
4.Water is pumped 9 mi from a reservoir at elevation 100 ft to a second reservoir at elevation 210 ft. The pipeline connecting the reservoirs has a 54-in diameter. It is concrete and has an absolute roughness of 0.003. If the flow is 25 mgd and pumping station efficiency is 80%, what will be the monthly power bill if electricity costs 3 cents/kwh?