Question
A disc of radius 10cm is rotating about its axis at an angular speed of 20rad/s. Find the linear speed of:
- A point on the rim.
- The middle point of a radius.
✓
Answer
A disc of radius = 10cm = 0.1m Angular velocity = 20rad/s $\therefore$ Linear velocity on the rim $=\omega\text{r}=20\times0.1=2\text{m/s}$ $\therefore$ Linear velocity at the middle of radius $=\frac{\omega\text{r}}{2}=20\times\frac{(0.1)}{2}=1\text{m/s}.$
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