Mechanical Engineering Answers

a gear train consisting of bevel gears, spur gears and a worm and worm

gear. The bevel pinion is mounted on a shaft driven by a V-belt on pulley. If pulley 2 rotates at

1200 r.p.m. in the direction shown, find the speed and direction of rotation of gear 9.

a compound gear train in which, wheel A is fixed to the driving shaft, B-C are

compounded , D is idle, and E is fixed on the driven shaft. If gear A rotates at 1000 r.p.m find

the speed and direction of E. driven shaft.

Stone A is hurled vertically upwards from a tower of height h with a speed vA0 . Simultaneously, stone B is thrown vertically upwards from the ground with a speed of vB0.

Given:

h=30m ; vA0=15m/s ; vB0=25m/s ; g=9.81m/s2 Find:

1. At which height and time do the stones fly past another?

2. At this time, what is the speed of stone A relative to stone B?

A steam engine isentropically expands 5 kg/sec of steam from 0.68 Mpa,

220°C, the exhaust is dry and saturated. Determine (a) the work of nonflow

process (b) the final temperature, and (c) the work of a steady flow process.

Water at 2.5 Mpa and 200°C is heated at constant temperature up to a

quality of 80%. Find (a) the quantity of heat received by the water, (b) the

change in internal energy, and (c) the work of nonflow process. (HINT:

table 4 needed)

Five kg of water vapour are contained at 150 kPa ad 90 per cent quality in a

suitable enclosure. Calculate the heat which must be added in order to just

produce a saturated vapor. What will the pressure be at the end of the

heating process?

design a flat belt (cross) to drive. the center distance between shafts is 5 m, velocity ratio=2.25, angular speed 600 rpm of the driving pulley, 60 hp, light shock.

a one dimensional steady flow is given by the following velocity;

"u=\\frac{2}{\\gamma+1}(\\frac xt-a_0)"

And density field;

"\\frac{\\rho}{\\rho_0}=(\\frac{\\gamma -1}{\\gamma+1}\\frac xt\\frac{1}{a_0}+\\frac{2}{\\gamma+1})^{\\frac{2}{\\gamma-1}}"

a)Calculate the substantial change of density.

b) check the validity of the continuity equation

"\\frac{D\\rho}{Dt}+\\rho\\frac{\\partial u}{\\partial x}=0"

for this flow field.

Explain the difference between an isothermal and an adiabatic expansion of a gas .

20020 m ^ 3 the gas in question 7 at a pressure of 1 bar is compressed to 70020 m ^ 3 adiabatic change . Calculate the:

a) ratio of the specific heat capacities y

b) final pressure

Explain briefly why a gas has two specific heat capacities.

0.28 kg of a gas is heated from 29 °C to 68°C. The specific heat capacity of the gas at constant volume is Cv = 0.72 kJ/kgK and the specific heat capacity at constant pressure Cp =1.01 kJ/kgK Calculate the change in:

a) Enthalpy

b)Internal energy

c) Flow energy