Question

1) Speed of bob?2)Direct measurement of centripetal Force: ?3)Show calculation for the speed of the bob:(write formula first, then insert value with unit, then find the result with unit)

Answer 1

We are given the time for an object to complete 20 revolutions in a circular path. To determine the velocity of the object we need to use the following formula:

`v=(S)/(T)`

Where:

`\begin{gathered} v=\text{ velocity} \\ S=\text{ lenght of the circular path (circumpherence)} \\ T=\text{ period} \end{gathered}`

To determine the value of "S" we use the following:

`S=2\pi r`

Where:

`r=\text{ radius}`

Now, we substitute in the formula for the velocity:

`v=(2\pi r)/(T)`

To determine the period we need to divide the time to complete the 20 revolutions by the number of revolutions, like this:

`T=(t)/(20)`

For example, let's take the first value and plug it into the formula:

`T=\frac{24.09s}{20\text{rev}}=1.2s`

Now, we plug in the value of the radius and the period in the formula for the speed and we get:

`v=(2\pi(0.22m))/(1.2s)`

Solving the operations:

`v=1.15(m)/(s)`

Therefore, the velocity of the bob is 1.15 m/s.