The number of revolutions of two pulleys is inversely proportional to their diameters. If a 24-inch diameter pulley making 400 revolutions per minute is belted to an 8-inch diameter pulley, find the number of revolutions per minute of the smaller pulley.

Respuesta :

Answer:

Number of revolution of smaller pulley of 8 inches is 1200 revolution per minute.

Solution:

Given that number of revolution of two pulleys is inversely proportional to their diameter.

Let say diameter of two pulley be [tex]\mathrm{d}_{1} \text { and } \mathrm{d}_{2}[/tex]

And revolution of two pulleys be [tex]\mathrm{r}_{1} \text { and } \mathrm{r}_{2}[/tex]

From given information  [tex]\mathrm{d}_{1}[/tex] is inversely proportional to [tex]\mathrm{r}_{1}[/tex] and [tex]\mathrm{d}_{2}[/tex] is inversely proportional to [tex]\mathbf{r}_{2}[/tex]

Assuming k be constant of proportionality we get

[tex]\mathrm{d}_{1}=\frac{k}{r_{1}} \text { and } d_{2}=\frac{k}{r_{2}}[/tex]

so we get

[tex]\frac{d_{1}}{d_{2}}=\frac{r_{2}}{r_{1}}[/tex]

Given that [tex]{d}_{1}[/tex] = 24 inches, [tex]{r}_{1}[/tex] = 400 revolution per minute , [tex]{d}_{2}[/tex] = 8 inches. we need to calculate [tex]{r}_{2}[/tex]

[tex]\frac{24}{8}=\frac{r_{2}}{400}[/tex]

[tex]{r}_{2} = 24 \times \frac{400}{8}[/tex] = 1200 revolutions per minute.

Hence number of revolution of smaller pulley of 8 inches is 1200 revolution per minute.