Machine-translated by Google. Questions are authored in English.
Top

Discussion

The velocity ratio of belt drive can be expressed mathematically as :

Where :
N1 = Speed of driver in r.p.m
N2 = Speed of follower in r.p.m
d1 = Diameter of driver
d2 = Diameter of follower

  • A.\(\frac{N_{2}}{N_{1}} = \frac{d_{1}}{\pi . d_{2}}\)
  • B.\(\frac{N_{2}}{N_{1}} = \frac{d_{1}}{d_{2}}\)
  • C.\(\frac{N_{2}}{N_{1}} = \frac{d_{2}}{d_{1}}\)
  • D.\(\frac{N_{2}}{N_{1}} = \frac{\pi . d_{1}}{d_{2}}\)

Answer: B

The velocity ratio is \(\frac{N_2}{N_1} = \frac{d_1}{d_2}\).

If the belt does not slip, every point on it moves at the same linear speed, so the rim speeds of the two pulleys are equal:

\[ \begin{aligned} \pi d_1 N_1 &= \pi d_2 N_2 \\ \frac{N_2}{N_1} &= \frac{d_1}{d_2} \end{aligned} \]

The speeds are inversely proportional to the diameters, so the smaller follower runs faster. The \(\pi\) appears on both sides and cancels, which rules out the two options that keep it, and \(\frac{d_2}{d_1}\) inverts the ratio.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.

Subject Categories

Examination Categories

About Us

ExamsRepo

Copyright © 2026 ExamsRepo . All Rights Reserved . With