CA2 Mechanics Questions PDF

1.a Write the alphabet of your choice answer in the CA test answer book mentioned the question number and subdivision number i. A member under the action of three forces will be in equilibrium if a.The resultant of the forces is zero b.all the forces are equal in magn...

1.a Write the alphabet of your choice answer in the CA test answer book mentioned the question number and subdivision number i. A member under the action of three forces will be in equilibrium if a.The resultant of the forces is zero b.all the forces are equal in magnitude, parallel in direction and opposite in sense. c.the line of action of all the forces intersect at a common point. Choose the correct statement among the above three. A) i), (ii) & (iii) B) (ii) & (iii) C) (i) & (iii) D) (i) & (ii) ii. For equilibrium of two-force members, the two forces should be A)Equal and opposite. B) Parallel to each other. C) Equal and collinear D) Equal, opposite and collinear iii. A member under the action of three forces will be in equilibrium if the resultant of the forces is zero and the line of action of the forces intersect at a point known as A) Point of contraflexure C) Point of inflection B) Point of concurrency D)Point of application of force iv. A ________ is a sketch or diagram of a part isolated from the mechanism along with forces and couples in order to determine the nature of forces acting on it. v. The torque T' on the link 'OA' for the force system shown in Fig.1 is _______Nm in ______direction. 1.b.l. A slider-crank mechanism with the following dimensions: OA = 100 mm and AB = 450 mm, is acted upon by a force 'F' on the slider as shown in Fig.2. An input torque T = 155 Nm is applied on the link 'OA' along the clockwise direction to maintain the system under static equilibrium. Determine the magnitude and direction of the force 'F.' 1.b. ii. For the four-bar mechanism shown in Fig.3 determine the magnitude and direction of torque (T2) exerted on the link AB. The dimensions of the links are AD=800mm, AB=300 mm, BC = 700 mm, and CD = 400 mm. Link CD is subjected to T4 = 20(counter clockwise). 1.c. A four-bar mechanism shown in Fig.4 is acted upon by a force P=100 N at 120°. The dimensions of various links are: AB = 40 mm, BC 60 mm, CD50 mm, AD = 30 mm, and DE = 20 mm. Determine the input torque on link 'AB' for the static equilibrium of the mechanism. 2. a. Write the alphabet of your choice answer in the CA test answer book mentioning question i.In a 4-stroke IC engine, the ideal turning moment diagram during compression stroke is A) Positive throughout B) Negative throughout C) Positive during the major portion of the stroke then goes negative D) Negative during the major portion of the stroke then goes positive II. The material which is widely used for the manufacturing of worm gears is A) Cast iron B) High Carbon Steel C) Phosphor Bronze D) Nylon 66 lIl. In the case of cycloidal tooth profile gears, A) the pressure angle is always constant through the contact B) the path of contact is a straight line C) the variation in centre distance affects the angular speed ratio D) interference is more Write the answer for the following Fill in the blanks questions in the CA test answer book mentioning the question number and subdivision number. iv. Consider a spur gear with a circular pitch of 4 mm and a pitch circle diameter of 28 mm. The number of teeth of the gear is _____________ v. The speed of an engine varies from 210 rad/s to 190 rad/s. During the cycle, the maximum fluctuation of energy is found to be 400 Nm. The mass moment of inertia of the flywheel (rim type) is______ kg/m² 2. b.l. The turning moment diagram for a multi cylinder engine shown in Fig.5 has been drawn to a scale of 1mm = 5000 Nm vertically and 1mm = 3.5 deg along the horizontal direction. The areas between the output torque curve and resistance line taken in order from one end are: -340, +21, -245, +300, -118, +230, -225 and +377 mm2 when the engine is running at 180 rpm. If the mass of the disc flywheel is 1000 kg and the total fluctuation of speed is not to exceed 3% of the mean speed, find the minimum value of the radius of gyration.(5 marks) b.ii. Sketch two teeth of a spur gear and illustrate the following: A. Pitch circle B. Addendum circle and addendum, C. Dedendum circle and dedendum, D. Face and face width E. Flank F. Top land and bottom land. Also, explain the above terms. 2. c. In a machine, the intermittent operations demand the torque to be applied as follows: a. During the first half-revolution, the torque increases uniformly from 800 Nm to 3000 Nm b. During the next one revolution, the torque remains constant. c. During the next one revolution, the torque decreases uniformly from 3000 Nm to 800 Nm d. During the last half-revolution, the torque remains constant. Thus, a cycle is completed as shown in Fig 6. The motor to which the machine is coupled exerts a constant torque at a mean speed of 250 rpm. A flywheel of mass 1800 kg and a radius of gyration of 500 mm is fitted to the shaft. Determine: 1) The power of the motor and 2) Total fluctuation of the speed of shaft