Question

A manufator makes two different sizes of spherical ball bEARINGS for use in motors. If the radius of the larger ball bearing is twice the radius of the smaller one, then the volume of the larger ball bearing is how many times the volume of the smaller one? EXPLAIN!

A) 2
B) 4
C) 6
D) 8

Answer 1

Option D is the answer.

Explanation:

Volume of sphere is given as:

`(4)/(3)\pi r^(3)`

Case 1:

Lets say the radius is 3 cm.

Volume =
`(4)/(3)*3.14*3*3*3`

= 113.04 cubic cm

Case 2:

Lets say the radius is twice 3 cm that is 6 cm.

Volume =
`(4)/(3)*3.14*6*6*6`

= 904.32 cubic cm.

The volume of the larger ball is
`(904.32)/(113.04)` = 8 times the smaller one.

So, the answer is option D : 8 times.