Engineering Answers

A four-cylinder petrol engine has a swept volume of 2000 cm3, and the clearance volume

in each cylinder is 60 cm3. Calculate the air-standard thermal efficiency. lf the induction

conditions are 1 bar and 24oC, and the maximum cycle temperature is 1400oC, calculate

the mean effective pressure based on the otto air-standard cycle.

The winner of lotto prize is given the choice of a one time payment of $1,000,000 or a guaranted $80,000 per year for 20 years. If the value of money is 5%, which option should the winner choose?

A Caesar Company has a capital investment of $67,000 and returns $12,000 per year for 5 years. At a 15% MARR, is this a good investment?

Calculate the power that can be transmitted at 300 rpm by a hollow steel shaft of 75 mm external diameter and 50 mm internal diameter when the permissible shear stress for the steel is 70 N/mm2 and the maximum torque is 1.3 times the mean. Compare the strength of this hollow shaft with that of a solid shaft. The same material, weight and length of both the shafts are same.

Find the diameter of the solid shaft to transmit 90 KW at 160 rpm such that the shear stress is limited to 60 N/mm2. The maximum torque is likely to exceed the mean torque by 20%. Also find the permissible length of the shaft, if the twist is not to exceed 1° over the entire length. Take rigidity modulus as 0.8×105N/mm2.

A steel shaft is to require transmitting 75 KW power at 100 rpm and the maximum twisting moment is 13% greater than the mean. Find the diameter of the steel shaft if the maximum stress is 70 N/mm2. Also determine the angle of twist in a length of 3 m of the shaft. Assume the modules of rigidity for steel as 90 KN/mm2.

A thin cylindrical pipe with an inside diameter of 200 mm is 4 mm thick and fitted with end covers. It is subjected to an internal pressure of 4,8 MPa. Calculate the circumferential and longitudinal stress induced. Which axially applied compressive load would reduce the longitudinal stress to zero

1. Write an algorithm and draw the flowchart that will ask the user to enter 3 real

numbers (x,y and z) as input. The algorithm will calculate and print the

following;

a. The area of a circle by using x as diameter. (Consider pi as 3.14)

b. The area of a rectangle by using y and z as both sides.

c. The area of a triangle by using x as height and z as base

Air enters a compressor with a stagnation pressure of 100 kPa and a stagnation

temperature of 27°C, and it is compressed to a stagnation pressure of 900 kPa.

Assuming the compression process to be isentropic, determine the power input to the

compressor for a mass flow rate of 0.02 kg/s.