Question

Calculate the time period of the waveform y(t)=7cos(54πt+2π÷4).

(a) .055 sec

(b) .037 sec

(c) .023 sec

(d) .017 sec

I had been asked this question in an online quiz.

The above asked question is from Energy Relations During Starting topic in chapter Starting of Electric Drives

Answer 1

Correct answer is (b) .037 sec

The explanation is: The fundamental time period of the cosine wave is 2π. The time period of y(t) is 2π÷54π=.037 sec. The time period is independent of phase shifting and time shifting.