Question

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

(a) t/s

(b) t/2s

(c) t/2r

(d) t/r

I had been asked this question in a job interview.

The origin of the question is Flywheel in a Punching Press in section Turning Moment Diagrams and Flywheel of Machine Dynamics

Answer 1

The correct answer is (b) t/2s

For explanation: The values of θ1 and  θ2 may be determined only if the crank radius (r), length of connecting rod (l) and the relative position of the job with respect to the crankshaft axis are known, in their absence we use the relation  (θ2 –θ1)/2π = t/2s.