Test: Engineering Equipments - 3 - Civil Engineering (CE) MCQ

Calculating Time Taken for One Round Trip

• Speed while pushing earth = 2.4 kmph


• Speed while returning empty = 6 kmph


• Time lost in loading and shifting gears per trip = 18 seconds


• Distance of one round trip = 30 m = 0.03 km


• Time taken for one round trip = (0.03 / 2.4) + (0.03 / 6) + 18/3600 hours


• Time taken for one round trip = 0.0125 + 0.005 + 0.005 = 0.0225 hours

 

Calculating Number of Trips per Hour

• Operating factor = 50 min/hour = 50/60 = 5/6 hours


• Time taken for one round trip = 0.0225 hours


• Number of trips made per hour = 5/6 / 0.0225 = 37 trips

Therefore, the number of trips made per hour is 37. Hence, the correct answer is option D.

Advantages of ADT over RDT are :
(i) Higher Maneuverability;
(ii) Lower turning radius
(iii) Higher tractive effort
(iv) Better operator comfort
(v) Faster cycle times and therefore low fleet costs

Back hoe or hoe can be used for digging trenches where precise control of depth is needed. Power shovels can be used to excavate the earth and load it into the trucks or other hauling equipments waiting nearby. They are capable of excavating all classes of earth except the solid rocks without loosening.. A dragline is designed to excavate below the level of the machine and need not to go into a pit or hole for excavating the earth. When the excavated earth is to be deposited on nearby banks or dams, it is better to use dragline with a long boom enough to dispose of the earth in one operation, eliminating the need of hauling units thereby reducing the cost of handling the earth. A dragline is excellent for excavating trenches without shoring.
The clamshell bucket is designed to excavate material in vertical direction and it is primarily used for handling loose materials such as sand, gravel, crushed stone, coal, etc.

By increasing angle of swim, the output of dragline will be reduced since output will be maximum at optimum depth of cut, so it will be further reduced if depth of cut is more or less than optimum depth of cut.

Cost price of machine = ₹ 1000000 Salvage value = ₹ 150000
at end of 10 years
∴ Depreciation per year

∴ Book value after to 5 years
= 1000000-85000x5
= ₹ 575000

This can be computed:as follows:
Depreciation in 1^st year, using double declining balance method

Book value after 1^st year
= 2000000 - 500000 = 1500000 
Depreciation in 2^nd year

Book value after 2^nd year
= 1500000 - 375000 = ₹ 1125000 
Depreciation in 3^rd year

Operating factor = Time ratio for which equipment actually works in one hour 
∴ Actual operating time = operating factor x 60 = 48 minutes.
Cycle Lime = Hauling time + Returning time + Fixed time 

Number of cycles = 48/9.06 = 5.3

Economic life is defined as the age of replacement that maximizes the profit returns from the equipment or minimizes the cumulative hourly owing and operating cost. The termination of economic life does not mean disposal of the equipment.