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a belt is placed around a pulley 41 cm in diameter and rotating at 242 rpm, what is the linear speed in m/s of the belt

1 Answer

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Given

d: diameter

d = 41 cm

We need radius information so we will calculate it:

r: radius

r = d/2

r = 41/2

r = 20.5 cm

Rotating speed

w = 242 rpm

Procedure

At a distance r from the center of the rotation, a point on the object has a linear speed equal to the angular speed multiplied by the distance r. The units of linear speed are meters per second, m/s.


v=\omega r

But before using the formula we need to have all the units in the same system. So we need to go from rpm to rad/s and from cm to m


\begin{gathered} 242\cdot\frac{\text{rev}}{\min}\cdot\frac{2\text{ pi rad }}{1\text{ rev}}\cdot\frac{1\text{ min}}{60\text{ s}} \\ 25.34\text{ rad/s} \\ \\ 20.5\text{ cm}\cdot\frac{1m}{100\operatorname{cm}} \\ 0.205\text{ m} \end{gathered}

Now we can calculate the linear velocity of the belt.


\begin{gathered} v=\omega r \\ v=25.34\text{ rad/s}\cdot0.205\text{ m} \\ v=5.1947\text{ m/s} \end{gathered}

Answer

The linear velocity of the belt would be 5.2 m/s.

User Jerin
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