Engineering Mechanics

Chapter 9 : Applications of Friction „„„„„ 169 Example 9.14. A screw jack has a square thread of 75 mm mean diameter and 15 mm p ...

(^170) „„„„„ A Textbook of Engineering Mechanics EXERCISE 9.3 A square threaded screw jack of mean diameter 25 mm and a pitch o ...

Chapter 10 : Principles of Lifting Machines „„„„„ 171 171 Principles of Lifting Machines Contents Introduction. Simple Machine. ...

(^172) „„„„„ A Textbook of Engineering Mechanics 10.2. SIMPLE MACHINE In a broad sense, a simple machine may be defined as a dev ...

Chapter 10 : Principles of Lifting Machines „„„„„ 173 Let W = Load lifted by the machine, P = Effort required to lift the load, ...

(^174) „„„„„ A Textbook of Engineering Mechanics We know that input of the machine = P × y ...(i) and output of the machine = W ...

Chapter 10 : Principles of Lifting Machines „„„„„ 175 Example 10.3. In a lifting machine, whose velocity ratio is 50, an effort ...

(^176) „„„„„ A Textbook of Engineering Mechanics P' = Ideal weight (neglecting the machine friction) required to lift the same w ...

Chapter 10 : Principles of Lifting Machines „„„„„ 177 Efficiency of the machine We know that M.A.^840 8.4 100 W P == = and effic ...

(^178) „„„„„ A Textbook of Engineering Mechanics W = Load lifted, and C = Another constant, which represents the machine frictio ...

Chapter 10 : Principles of Lifting Machines „„„„„ 179 Efficiency when P is 74 N and W is 2000 N We know that M.A.^200027 74 W P ...

(^180) „„„„„ A Textbook of Engineering Mechanics Effort required to run the machine at no load Substituting the value of W = 0 i ...

Chapter 10 : Principles of Lifting Machines „„„„„ 181 Mechanical advantage Substituting the value of W in the law of the machine ...

(^182) „„„„„ A Textbook of Engineering Mechanics Effort required to overcome the machine friction We know that effort required t ...

Chapter 10 : Principles of Lifting Machines „„„„„ 183 ∴ Law of the machine is given by the relation P = 0.08 W + 22.5 Ans. Effor ...

(^184) „„„„„ A Textbook of Engineering Mechanics What do you understand by the term ‘Reversibility’ of a machine? Explain the d ...

Chapter 11 : Simple Lifting Machines „„„„„ 185 185 Simple Lifting Machines 11.1. INTRODUCTION In the last chapter, we have discu ...

(^186) „„„„„ A Textbook of Engineering Mechanics then increase in the velocity ratio must increase its mechanical advantage. The ...

Chapter 11 : Simple Lifting Machines „„„„„ 187 and displacement of the load in one revolution = πd ...(ii) ∴ Distance moved by t ...

(^188) „„„„„ A Textbook of Engineering Mechanics 11.4.DIFFERENTIAL WHEEL AND AXLE Fig. 11.2. Differential wheel and axle. It is ...