Question

The angular velocity of a point with radius 8 feet is 10 pi radians per second. Find the speed of the point.

0.8pi ft/sec
1.25pi ft/sec
80pi ft/sec

Answer 1

Answer:
`80\pi\text{ ft/sec}`

Explanation:

Formula :
`\text{Speed= Angular velocity x Radius}` (1)

We are given that , The angular velocity of a point with radius 8 feet is 10 pi radians per second.

i.e. Radius = 8 feet

Angular velocity =
`10\pi` radians per second.

Then, the speed of the point will be :-

`\text{Speed= }10\pi * 8` [using (1)]

`=80\pi\text{ ft/sec}`

Hence, the speed of the point
`=80\pi\text{ ft/sec}`

Answer 2

80π feet/ second.

Explanation:

Angular velocity of a point = 10π radians per second

Radius of the circle is 8 feet.

We know the formula of angular velocity is

Angular velocity =
`(speed)/(radius)`

10π =
`(speed)/(8)`

Speed = 80π feet/ second.

Option C is the answer.