Mechanical Engineering Answers

A cube (40 mm) is resting on ground and all vertical faces are equally inclined to the vertical plane. A sectional plane, inclined to horizontal plane and perpendicular to the vertical plane is cutting the cube to get a regular hexagonal cutting shape (true shape) on cube. Find the angle of the cutting plane to the horizontal and draw the projections of cube (front view and sectional top view). Develop the true shape of the cutting surface.

A steady stream of air enters a horizontal compressor at the rate of 0.02 kg/s. The air temperature is 10o C at entry and 300o C at exit. The velocity of the air is 30 m/s at entry and 6 m/s at exit. During its passage through the compressor, the air experiences a heat loss of 105 kJ/kg of air. Calculate: (a) The change in kinetic energy per kg of air (b) The change in enthalpy per kg of air (c) The work done per kg of air (d) The power required to drive the compressor (e) The volume of air entering the compressor per second (f) The flow area of the entry pipe if the entry pressure is 1 bar Take R = 0.287 kJ/kgK and cp = 1.005 kJ/kgK

he engine mechanism shown in Fig. 8.38 has crank OB = 50 mm and length of connecting rod A B = 225 mm. The centre of gravity of the rod is at G which is 75 mm from B. The engine speed is 200r.p.m. For the position shown, in which OB is turned 45° from O A, Find 1. the velocity of G and the angular velocity of A B, and 2. the acceleration of G and angular acceleration of A B.

Cone A turns 125 rpm and cone B turns 164 rpm. Calculate the cone angle for the smaller cone if the shaft angle is 60°. Write your answer to 2 decimal places

`The lift force experienced by a spherical ball of radius 600 millimeters rotating about itsOwn axis at a speed of 10m s in 3 stream of aur at 20 ^{°}C a during the coincidence of thestagnation point is`

3.9. A hunter desires to go to a point northeast but because of a canyon

he goes ½ mile due east and then turns left and travels ¾ mile in a straight

direction in degrees did he travel in going the ¾ mile?

3-7. A stream has parallel banks and ie 1000 ft across. A boat has traveled

500 it in a straight line making 30° with the bank. At this instant find the distance the boat has gone parallel to the bank and the shortest distance to

the opposite bank.

3-5. A vector is 4 in. long and has a direction-sense of 60°.

(a) Resolve

the vector into horizontal and vertical components,

(b) Find the components

of this vector on lines making 15° and 75° with the horizontal. (c) Find the

components of this vector along and perpendicular to a line making 30° with

the horizontal,

3-3.

Given five vectors whose lengths and direction-senses are as follows:

Ac, is 1.5 in. long and 90°; Aa, is 1.25 in, long and 315°; Aay is 2 in. long and

0°; AQ, is 1.25 in. long and 225°; Ad, is 1.5 in. long and 45°. Find the vector

sum of the first four, and subtract Ad, from this resultant vector.

3-1. A vector Bb is 1 in. long and has a direction-sense of 45°. Vector Cc

is 1½ in. long and has a direction-sense of 150°. Find their vector sum.