GENERAL KNOWLEDGE PROBLEM SOLVING
(VOLUME 1)
Question 1: Suppose you have a micro turbine with a blade diameter of 1 m (about 3 ft) and an efficiency of 20%. Calculate the electricity it can generate for your home at an air speed of 6 m/sec (about 13.4 mph). Assume air density to be 1.2 kg/m3.
A) 30.3 Watts
B) 40.3 Watts
C) 20.3 Watts
D) 10. 3 Watts
SOLUTION: https://youtu.be/46phy6Dycwk
Question 2: Four 40-watt by 120 cm. fluorescent lamp, each producing 3,200 lumens of light, are installed in a room having a general dimension of 6.096 m x 15.24 m . Find the illumination on the floor (In foot-candle).
A) 15.8 fc
B) 14.8 fc
C) 13.8 fc
D) 12.8 fc
SOLUTION: https://youtu.be/46phy6Dycwk
Question 3: If Mechanical work is done at 1 ft-lb/s, what is its equivalent in watts?
A) 0.35 W
B) 1.35 W
C) 3.35 W hp
D) 3.33 W
SOLUTION: https://youtu.be/46phy6Dycwk
Question 4: A clay soil has a sand: silt: clay ratio of 1:3:4. It has a pH of 5.2 and Organic matter content of 6.5%. Determine the soil erodibility factor K.
A) 0.356
B) 0.556
C) 0.256
D) 0.156
SOLUTION: https://youtu.be/46phy6Dycwk
Question 5: Give the estimated mechanical power output of a windmill having a rotor diameter of 8 meters if wind velocity is 3 m/s.
A) 438.95 W
B) 337.83 W
C) 236.69 W
D) 135.65 W
SOLUTION: https://youtu.be/46phy6Dycwk
Question 6: What is the peak solar power generation per charging channel of a solar battery charging station equipped with 12 units of 75 watt-peak 12-volt solar module? The system is divided into 3 charging channels, each channel has 4 modules connected in parallel. Assume 80% overall efficiency.
A) 1240 Watt-peak
B) 2400 Watt-peak
C) 240 Watt-peak
D) 200 Watt-peak
SOLUTION: https://youtu.be/46phy6Dycwk
Question 7: Determine the kinetic energy of per unit area if a rainfall event occurring within 10 mins has an intensity of 60 mm/hr.
A) 0.74 MJ/ha
B) 2147 MJ/ha
C) 2.74 MJ/ha
D) 12.7 MJ/ha
SOLUTION: https://youtu.be/46phy6Dycwk
Question 8: Your body is burning chemical energy at a rate of 620 W. You are also losing heat to the surroundings via conductive heat transfer through a layer of wool of thickness 5 mm. If your core temperature stays stable at 37OC and your surface area is 1.6 m2, how much power are you using to perform tasks in a cold environment where the temperature is 15OC? Thermal conductivity of wool = 0.07 W/(m·K).
A) 2110.88 KW
B) 127.2 W
C) 12070.2 W
D) 5127.2 W
SOLUTION: https://youtu.be/46phy6Dycwk
Question 9: Air at 1 atm and 17OC occupies an initial volume of 1,000 cm3 in a cylinder. The air is confined by a piston which has a constant restraining force so that the gas pressure always remains constant. Heat is added to the air until its temperature reaches 257OC. Calculate the work done by the gas. R = 0.287 kJ/kg·K.
A) 38.88 J
B) 90.86 J
C) 9.86 J
D) 83.86 J
SOLUTION: https://youtu.be/46phy6Dycwk
Question 10: Determine the required digester volume of a biogas plant that will accommodate manure from a broiler farm having a capacity of 20,000 heads of mixed ages. Use 30-day retention period and 1:1 manure-water ratio. The mean daily manure production of broiler is 0.025 kg/head while its specific gas production for 30-day manure retention period is 0.062 m3/kg. Chicken dung density is 950 kg/m3.
A) 5.2 cu.m.
B) 25.2 cu.m.
C) 5.2 cu.m.
D) 75 cu.m.
SOLUTION: https://youtu.be/46phy6Dycwk
Question 11: WAnemometers at 2.5 m and 40 m on a tower record wind speed of 2 and 5 m/s respectively. Compute wind speeds at 5 and 30 m.
A) 20.51 m.s , 14.55 m/s
B) 2.51 m.s , 4.55 m/s
C) 120.51 m.s , 114.55 m/s
D) 200.51 m.s , 140.55 m/s
SOLUTION: https://youtu.be/46phy6Dycwk
Question 12: An aquifer, with permeability of 15ft/day, is overlain by an impermeable layer of hard clay material. A 12 in-diameter fully penetrating well drilled into the aquifer yield 20 Lps constant discharge. What is the thickness of the aquifer if the constant drawdown of 20ft below the overlaying impermeable layer created a 3000 ft cone of depression?
A) 952 ft.
B) 4 ft
C) 100 ft
D) 259 ft.
SOLUTION: https://youtu.be/46phy6Dycwk
Question 13:The density of two liquids (A and B) is given as 1000 kg/m3 and 600 kg/m3, respectively. The two liquids are mixed in a certain proportion and the density of the resulting liquid is 850 kg/m3. How much of liquid B (in grams) does 1 kg of the mixture contain?
A) 4.70 grams
B) 64.70 grams
C) 264.70 grams
D) 1264.70 grams
SOLUTION: https://youtu.be/46phy6Dycwk
Question 14:A simple saturated refrigeration cycle for R-12 system operates at an evaporating temperature of -5OC and a condensing temperature of 40OC. Determine the COP of the system.
A) 195.9
B) 4.88
C) 27.8
D) 368.6
SOLUTION: https://youtu.be/46phy6Dycwk
Question 15:A block of mass M = 10 kg is sitting on a surface inclined at angle θ = 45°. Given that the coefficient of static friction is μs = 0.5 between block and surface, what is the minimum force necessary to prevent slipping?
A) 44.65 N
B) 346.5 N
C) 3,465 N
D) 34.65 N
SOLUTION: https://youtu.be/46phy6Dycwk
Question 16:A ¼ in steel shaft transmits 80 in-lb torque. The effective length of shaft is 12 in, the modulus elasticity in shear is 12 000 000 psi. Find the angular deflection in degrees.
A) 19.5 degrees
B) 15.59 degrees
C) 11.95 degrees
D) 1.95 degrees
SOLUTION: https://youtu.be/46phy6Dycwk
Question 17: A barangay road 6.00 meters wide and 2 kilometers long after base preparation requires concreting. How many 50-kg bags of cement are required using class A concrete is the slab is 6 inches thick.
A) 12,802 bags
B) 11,802 bags
C) 1,802 bags
D) 21,802 bags
SOLUTION: https://youtu.be/46phy6Dycwk
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