Question

What would the speed of an object be if it had a period of 5 seconds and a radius of 2m?

Answer 1

2 m/s approximately

Step-by-step explanation:

We can use linear speed formula to solve this problem as we are given with period and radius:

`\displaystyle{v = (2\pi r)/(T)}`

v is velocity, r is radius and T is period. Substitute in known values:

`\displaystyle{v = (2\pi * 2)/(5)} \\ \\ \displaystyle{v = (4\pi)/(5)} \\ \\ \displaystyle{v = (4 * 3.14)/(5)} \\ \\ \displaystyle{v = (10)/(5) } \\ \\ \displaystyle{v = 2 \: \text{m/s}}`

As for why 4*3.14 becomes 10, it's due to the significant figure rules of multiplication. Since it's 1 significant figure times 3 significant figures, we use the lowest significant figures to determine the answer. Hence, why it's not 12 but 10 instead.