Dynamics Of Machines Set 2 MCQs

Q1 | For a 4 cylinder engine, when the pressure inside the cylinders exceeds the atmospheric pressure then.

work is done by the gases

work is done on the gases

work is done on the piston wall

work is done by the piston wall

Q2 | In a punching press, which of the following quantity is constant?

load

torque

angular velocity

angle of rotation

Q3 | In a punching press, load is 0 at the time of punching.

true

false

Q4 | The maximum shear force required for punching depends on

sheared area

length of the plate

speed of the flywheel

total load

Q5 | A machine punching 38 mm holes in 32 mm thick plate requires 7 N-m of energy per sq. mm of sheared area, find the maximum shear force required.

26.7 kn

53.4 kn c) 13.35 kn d) 106.8 kn

Q6 | The relation between stroke punch s and radius of crank r is

s=r

s=2r

s=4r

s=r/2

Q7 | If the stroke punch is 100mm, find the radius of the crank in mm.

200

100

50 d) 400

Q8 | Energy during actual punching operation is same as the energy supplied by the motor.

true

false

Q9 | The balance energy required for punching is supplied by the flywheel by

increase in its kinetic energy

decrease in its kinetic energy

decrease in its potential energy

by variation of mass

Q10 | When the length of the connecting rod is unknown then the value (θ2 –θ1)/2π is equal to

t/s

t/2s

t/2r

t/r

Q11 | The size of a cam depends upon

base circle

pitch circle

prime circle

pitch curve

Q12 | The angle between the direction of the follower motion and a normal to the pitch curve is called

pitch angle

prime angle

base angle

pressure angle

Q13 | A circle drawn with centre as the cam centre and radius equal to the distance between the cam centre and the point on the pitch curve at which the pressure angle is maximum, is called

base circle

pitch circle

prime circle

none of the mentioned

Q14 | The cam follower generally used in automobile engines is

knife edge follower

flat faced follower

spherical faced follower

roller follower

Q15 | The cam follower extensively used in air- craft engines is

knife edge follower

flat faced follower

spherical faced follower

roller follower

Q16 | In a radial cam, the follower moves

in a direction perpendicular to the cam axis

in a direction parallel to the cam axis

in any direction irrespective of the cam axis

along the cam axis

Q17 | A radial follower is one

that reciprocates in the guides

that oscillates

in which the follower translates along an axis passing through the cam centre of rotation.

none of the mentioned

Q18 | Ofset is provided to a cam follower mechanism to

minimise the side thrust

accelerate

avoid jerk

none of the mentioned

Q19 | For low and moderate speed engines, the cam follower should move with

uniform velocity

simple harmonic motion

uniform acceleration and retardation

cycloidal motion

Q20 | For high speed engines, the cam follower should move with

uniform velocity

simple harmonic motion

uniform acceleration and retardation

cycloidal motion

Q21 | Which of the following displacement diagrams should be chosen for better dynamic performance of a cam-follower mechanism ?

simple hormonic motion

parabolic motion

cycloidal motion

none of the mentioned

Q22 | The linear velocity of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by

ω(r1-r2)sinθ

ω(r1-r2)cosθ

ωr1+r2)sinθsec2θ

ω(r1+r2)cosθcosec2θ

Q23 | The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by

r(1-cosθ)

r(1-sinθ)

(r-r1)(1-cosθ)

(r-r1)(1-sinθ)

Q24 | The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by

ω2×oq

ω2×oqsinθ

ω2×oqcosθ

ω2×oqtanθ

Q25 | Centre of masses of the system lies on the axis of rotation.

1, 2, 3 and 4

1, 2, and 3 only

2, 3 and 4 only

1, 3 and 4 only