Mechanical Engineering Answers

A multi-disc clutch has three discs on the driving shaft and two on the driven shaft. The inner diameter of the contact surface is 120 mm. The maximum pressure between the surface is limited to 0.1 N/mm2. Find the outer diameter for transmitting 25 kW at 1575 rpm. Assume uniform wear condition and coefficient of friction as 0.3.

A full journal bearing of 50 mm diameter and 100 mm long has a bearing pressure of 1.4 N/mm2. The speed of the journal is 900 r.p.m. and the ratio of journal diameter to the diametral clearance is 1000. The bearing is lubricated with oil whose absolute viscosity at the operating temperature of 75°C may be taken as 0.011 kg/m-s. The room temperature is 35°C. Find : 1. The amount of artificial cooling required, and 2. The mass of the lubricating oil required, if the difference between the outlet and inlet temperature of the oil is 10°C. Take specific heat of the oil as 1850 J / kg / °C.

A multi disc clutch, steel on bronze is to transmit 20 kW at 1440 rpm. The clutch is to be operated in oil with the coefficient of friction 0.08 and the average pressure is 0.3 MPa. Space limitation permits only 230 mm as outside diameter of the clutch. Assuming uniform pressure, determine: (i) Actual axial force required (W’) (ii) Actual maximum pressure (p’max) (iii) Actual average pressure (p’ave) Ratio of (Ri/Ro) can be chosen between 0.5 and 0.75 suitably and logically

Two tanks A and B contain 1 kg of air at 1 bar, 50oC and 3 bar, 50oC when
atmosphere is at 1 bar, 15oC. Identify the tank in which stored energy is
more. Also find the availability of air in each tank.

A telecommunications tower as shown has dimensions shown, and has a
Mass = 1.2 Tonnes,
(Acceleration due to Gravity ≈ 10 ms-2)

Data: Analysis: Calculation:
Reactions Analysis
3. Calculate the reaction at the LHS (Rl). Analyse one side of tower with 2 reactions.
Data: Analysis: Calculation:
Stress Analysis- for a balsa 1:100 scale-model prototype Qs4-6
4. Calculate the cross sectional area of the truss members of a 1:100 balsa tower.
Data: Analysis: Calculation:
5. Calculate the Stress in member ‘a’ if the load in the member is 250N.
Data: Analysis: Calculation:
6. Calculate the Stress in member ‘b’ if the load in the member is 120N.
Data: Analysis: Calculation:

an lvdt is used to measure the axial deformation of the simple bar of fig. 10.3. the uncertainty in this measurement is ±0.025 mm. a steel bar is to be used to measure a force of 1100 n with an uncertainty of 1 percent. determine a suitable diameter and length of rod for this measurement, assum- ing the rod dimensions will be known exactly

I would be grateful for your assistance with an equation regarding the force of a punch and increased force impact with a ring, with the same punch.
A stiletto impact comparison.
The Ring increased impact; hardness and surface area.

Ring material;
Stainless steel: 7.5 Mohs: Bulk Modulus mean 185.
Granite: 6.5 Mohs: Bulk Modulus mean 40.
Human bone 5 Mohs: Bulk Modulus mean 14.

Body Wt 85kg x Fist surface area 7.5cm x 5.5cm
Body Wt 85kg x Fist surface area 7.5cm x 5.5cm x Ring wt 18gr x surface area 17×17mm

The conventional punch measured 148 kg.
Punch speed about 20 miles per hour.
Punching forces in amateur boxing are around 2500 N @ 70 kg.
Exert about 700 N of force on the ground just stood still, punching force about 3.5 times body mass.
Punch speed 80 ms

Kind regards
Ian Harris

A single cylinder petrol engine has a volume compression ratio of 4:1, takes in a mixture of fuel and air at a temperature of 20°Cand its pressure is 101kPa. If the pressure at the end of the compression stroke is 1.5MPa what will be its final temperature?

Air initially at 75 psia and 65 0F is compressed to a final pressure of 300 psia and temperature of 320 0F. Find the polytropic exponent for the process

A steel rod subjected to compression is modeled by two bar elements as shown in figure 1. Determine the nodal displacement and the axial stress in each element. What other concerns should be examined?

0.5 m

E = 207 GPa

0.5 m

A = 500 mm

12KN

Figure(1)