81⟩ How does a hammer mill work?
Big hammers (not the kind you pound nails with) spin out with centrifugal force and beat whatever it is you are grinding into smaller pieces.
Mechanical Engineering
Home Engineering Mechanical Engineering
“Build your Mechanical Engineering knowledge by exploring Mechanical Engineering Interview Questions and Answers. And get preparation for Mechanical Engineering job by our Mechanical Engineering guide, tips, tutorial and interview questions and answers.”
164 Mechanical Engineering Questions And Answers
82⟩ How do you calculate cooling energy?
Required cooling involves calculating the heat leaks into the cooled space. This could involve solar loading, the heat leak through a wall or a window. Maybe the structural supports hold up a detector at cryogenic temperatures. Typically, you know something about how the amount of the heat leak varies with the temperature at its two sides. House insulation and windows have an R-value that tells you how much heat leaks through as a function of the internal and external temperatures.
Once you know the load, you can calculate the amount of energy required to provide that much cooling. An air conditioner sold in the United States will have an "Energy Efficiency Rating" that tells how many BTUs/hr of cooling are produced per watt of electrical power input. So if you need 5000 BTU of cooling and your A.C. has an EER of 10, you will need 5000/10 = 500 W of electrical power to run it.
In a country that uses a sensible unit system the cooling requirement and the electrical power, are both measured in Watts, so an A.C. will simply have a coefficient of performance (COP) which is the Watts of cooling per Watt of electrical power? COPs for typical air conditioners is about 3, so in the above example you would have calculated that you needed 1450 W of cooling, and with a COP of 3 you would need 480 W.
83⟩ How is natural gas better than LPG?
Without getting into the chemistry and physics of the two different types of gases, natural gas has a higher but output than liquid propane gas. In other words, higher the available energy output/more energy is efficient.
84⟩ How can heat be applied to acrylic?
In most hardware stores, you can find what has called a Heat Gun. Hold the heat gun about 6inches away from the acrylic you intend on bending say the bumper on a car. They are plastic these days, but will melt when you apply heat to them. Using a cold scraper, you can usually mold two pieces back together using the heat gun.
85⟩ What is the Device that converts sound energy into mechanical energy?
Sound energy is mechanical energy. No devices are required to make a conversion.
86⟩ Which conducts heat faster steel copper or brass?
Copper conducts heat faster than steel or brass. Any material that is good for conducting heat is also good for electricity in most cases. Wood terrible for transferring heat thus is also insulator for electric.
87⟩ What is a mechanism?
A mechanism is a system of moving parts that changes an input motion and force into a desired output motion and force.
88⟩ Who built the first rocket that Robert Goddard invented?
Goddard built his own early rockets.
89⟩ Accelerometers measure acceleration. How do you measure the moment of inertia?
You calculate it using your moment of inertia equations corresponding to the geometry of the object. There is no simple device I do not think that you can buy to just measure it.
90⟩ What is a slined joint?
Cotter Pin
91⟩ How pipe flanges are electrically insulated?
Pipe flanges are protected from corrosion by means of electrolysis, with dielectric flanges. The piping system is electrically insulated by what is called a sacrificial anode. A bag of readily corrodible metal is buried in the ground with a wire running from the pipe to the bag so that the sacrificial anode will corrode first. If any electrical current charges the pipe, it also serves as a ground.
92⟩ How do you convert 95 feet into square feet?
You cannot convert feet into square feet; they are two entirely different and incompatible units. Converting feet to square feet is like converting apples to oranges.
A linear foot is a unit of distance. A square foot is a unit of area. If you have a rectangular surface, you can compute the area in square feet by multiplying the length in feet by the width in feet. For example, a rectangular patio that is 12 feet wide by 15 feet long has an area of 12 x 15 = 180 square feet.
93⟩ Why would some industries select pneumatics over hydraulic?
Actually, there is need for air reservoir in industrial pneumatics systems. Hydraulics can handle more powerful applications than pneumatics for the same overall dimensions, or can be more compact for the same power.
94⟩ What is a Process Flow Diagram?
A Process Flow Diagram (or System Flow Diagram) shows the relationships between the major components in the system. It also has basic information concerning the material balance for the process.
95⟩ What is difference between mill and mill-drill?
Today many manufactures are combining machines; a mill/drill is one of these. It is a combination of a drill and a mill, a mill removes stock from material (usually metal, but not limited just to metal, it depends on your application), you use fluted cutters such-as end mills. The drill aspect of the machine is just that it drills holes, with the proper speed for the right size drill.
96⟩ What is a vee used for on the Vee Block?
It holds round/cylindrical material. It is usually used to judge the cylindricity of the cylindrical material.
Normally 90 degrees vee can be used for the marking of the cylindrical cross section surface, level checking.
97⟩ Where pneumatic system is used?
Any system needs redundancy in work needs pneumatics, because the compressor of the pneumatic system has periodical operations (intermittent work, not as hydraulic pump). The compressed air could be accumulated in tanks with high pressures and used even if the compressor failed.
98⟩ What is brain of the computer?
The processor (or CPU) is the brain of the computer. This is the part, which does all the "thinking", i.e. maths.
There is no information stored in the CPU, the information is held in the hard disk, and is fished out, acted on by the CPU, and so on.
99⟩ How many litres did 1 cubic meter contains?
1000 litre in a cubic meter
100⟩ Did Elevation affect weight?
The acceleration of Gravity is less, as you get further away from the center of the earth. This would cause you to weigh less. The equation for the force of gravity is GMm/(R^2). Where G is the universal Gravity Constant which is something like 6.67x10^ (-11) and M is the mass of the earth, and m is the mass of the weight being measured. R is the distance from the center of the earth that increases as you increase in altitude.
