DOM QUESTION PAPER - 2

QUESTION PAPER – 2

DYNAMICS OF MACHINES

QUE NO 1:-

(A) DESCRIBE EQUILIBRIUM OF TWO AND THREE FORCE MEMBERS WITH THE HELP OF NEAT DIAGRAM.

(B) FIG.1 SHOWS A QUATERNARY LINK ABCD UNDER THE ACTION OF FORCES F₁, F₂, F₃, AND F₄ ACTING AT A, B, C, AND D RESPECTIVELY. THE LINK IS IN STATIC EQUILIBRIUM. DETERMINE THE MAGNITUDE OF THE FORCES F₁ AND F₂ AND THE DIRECTION OF F₃.

QUE NO 2:-

THE CRANK AND CONNECTING ROD OF A VERTICAL PETROL ENGINE, RUNNING AT 1800 RPM ARE 60 MM AND 270 MM RESPECTIVELY. THE DIAMETER OF THE PISTON IS 100 MM AND THE MASS OF THE RECIPROCATING PARTS IS 1.2 KG. DURING THE EXPANSION STROKE WHEN THE CRANK HAS TURNED 20⁰ FROM THE TDC, THE GAS PRESSURE IS 650 KN/M².

DETERMINE THE (I) NET FORCE ON THE PISTON, (II) NET LOAD ON THE GUDGEON PIN, (III) THRUST ON THE CYLINDER WALLS, (IV) SPEED AT WHICH THE GUDGEON PIN LOAD IS REVERSED IN DIRECTION.

QUE NO 3:-

(A):- DEFINE INTERFERENCE AND PRESSURE ANGLE IN INVOLUTE PROFILE GEARS.

SHOW HOW INTERFERENCE IS AFFECTED BY PRESSURE ANGLE.

(B) TWO SPUR GEARS HAVE A VELOCITY RATIO OF 1/3. THE DRIVEN GEAR HAS 72 TEETH OF 8 MM MODULE AND ROTATES AT 300 RPM. CALCULATE THE NUMBER OF TEETH AND THE SPEED OF THE DRIVER. WHAT WILL BE THE PITCH LINE VELOCITIES?

QUE NO 4:-

AN EPICYLIC GEAR TRAIN CONSISTS OF AN ARM AND TWO GEARS A AND B HAVING 30 AND 40TEETH RESPECTIVELY. THE ARM ROTATES ABOUT THE CENTRE OF THE GEAR A AT A SPEED OF 80 RPM COUNTER- CLOCKWISE. DETERMINE THE SPEED OF THE GEAR B IF (I) THE GEAR A IS FIXED, AND (II) THE GEAR A REVOLVES AT 240 RPM CLOCKWISE INSTEAD OF BEING FIXED.

QUE NO 5:-

(A) WHAT ARE THE SELF LOCKING AND SELF ENERGIZING BRAKES? DERIVE AN EXPRESSION FOR RATIO OF TIGHT SIDE TENSIONS IN BAND AND BLOCK BRAKE.

(B) DESCRIBE THE WORKING OF A HARTNELL GOVERNOR WITH THE HELP OF NEAT DIAGRAM.

QUE NO 6:-

THE FOLLOWING DATA RELATE TO A FOUR-LINK MECHANISM:

A=55 MM, M_A=0.045 KG

B=165 MM, M_B=0.13 KG

C=80 MM, M_C=0.05 KG

D=150 MM, G_A=28 MM, Φ_A=0⁰

G_B=85 MM, Φ_B=15⁰, G_C=42 MM, ΦC=0⁰.

COMPLETE FORE BALANCING BY ADDING COUNTER MASSES TO THE INPUT AND OUTPUT LINKS IS DESIRED. DETERMINE THE MASS-DISTANCE VALUES AND ANGULAR POSITION OF EACH COUNTER MASS.

QUE NO 7:-

(A) DESCRIBE AN EXPRESSION FOR THE GYROSCOPIC STABILITY OF TWO WHEEL VEHICLE WHEN TAKING A TURN.

(B) EXPLAIN THE APPLICATION OF GYROSCOPIC PRINCIPLES TO NAVAL SHIPS WHILE STEERING, PITCHING AND ROLLING.

QUE NO 8:-

(A) DESCRIBE THE IMPORTANCE OF AUTOMATIC CONTROL.

(B) EXPLAIN OPEN LOOP AND CONTROL LOOP SYSTEMS WITH DIAGRAM AND NUMERICAL METHOD TO SOLVE THE PROBLEMS TAKING PRACTICAL EXAMPLE OF ANY MECHANICAL SYSTEM.14