THEORY OF MACHINES (ME-403) - Important Questions

In a slider-crank mechanism the crank is 150 mm long and connecting rod 600 mm long. Crank rotates at 100 rpm clockwise. For a crank angle of 45b0 from inner dead centre, determine velocity and acceleration of the piston/slider.

For the above slider-crank / reciprocating engine mechanism, determine the angular velocity and angular acceleration of the connecting rod at the given crank position, speed and acceleration.

Explain the inversions of a single slider-crank mechanism with neat sketches. Describe any three inversions with their engineering applications.

Explain the concept of inversions and illustrate the different inversions of a four-bar chain/mechanism with neat sketches.

A four-bar linkage has fixed link PS = 200 mm, crank PQ = 62.5 mm, coupler QR = 175 mm and rocker RS = 112.5 mm. Using Grashof's criterion determine the type/class of the mechanism and identify crank-rocker, double-crank or double-rocker.

State and explain D'Alembert's principle and its application in dynamic analysis of mechanisms.

Define cam terminology 014 base circle, prime circle, pitch circle, pressure angle, cam profile, lift/stroke of follower and period of dwell 014 with a neat sketch, and explain why a smaller pressure angle is preferable in cam design.

A radial knife-edge cam with lift 50 mm gives SHM rise for 120b0 of cam rotation, dwell for 60b0 and SHM return. Cam speed 60 rpm. Calculate maximum velocity and acceleration during SHM rise and SHM return.

A belt drive transmits 6 kW. Belt is 100 mm wide and 10 mm thick, distance between shafts 4 m. Calculate belt tensions on tight and loose sides and stress in open and crossed belt drives for given pulley diameters, speed and coefficient of friction 0.3.

Find the power transmitted by a belt running over a pulley of 600 mm diameter at 200 rpm. Coefficient of friction between belt and pulley is 0.25, angle of lap 160b0 and maximum tension in belt is 2 kN. State condition for maximum power.

Explain the construction and working principle of a single-plate clutch with a neat sketch.

Explain the working of block, band, internal and external shoe brakes with neat sketches. Compare the performance of block and band brakes for the same drum diameter.

State and explain the law of gearing. Discuss the importance of conjugate tooth profiles including involute profile in ensuring constant velocity ratio.

Explain the concepts of static balancing and dynamic balancing. Discuss the balancing of rotating masses in the same plane and in different planes.

Discuss briefly with neat sketches the longitudinal, transverse and torsional types of free vibration.

In an epicyclic sun-and-planet gear the pitch circle diameter of the internally toothed ring is 224 mm and module 4 mm. When the ring is stationary the spider carries planet, determine speed ratios and classify as simple, compound and epicyclic gear train.