# Math Help - how to calculate the length of this bar?

1. ## how to calculate the length of this bar?

Hey guys,

I am not sure if this question belongs to this forum but i am going to ask it anyways.

Imagine that you have a 45 feet cylinder and inside you have 2 bars. from top to bottom the bars don;t go straight down instead the bars the bars get into the bottom by going around the whole cilinder (similar to a spiral shape).

My question is, how do i compute the length of any of those 2 bars?, for sure it should be longer than the whole cylinder but i have no idea.

In the attached file, there are the details. It says that every 16 ft it makes a complete revolution.

Please let me know if anyone knows about this.

Thanks

2. Originally Posted by lgarcia
Hey guys,

I am not sure if this question belongs to this forum but i am going to ask it anyways.

Imagine that you have a 45 feet cylinder and inside you have 2 bars. from top to bottom the bars don;t go straight down instead the bars the bars get into the bottom by going around the whole cilinder (similar to a spiral shape).

My question is, how do i compute the length of any of those 2 bars?, for sure it should be longer than the whole cylinder but i have no idea.

In the attached file, there are the details. It says that every 16 ft it makes a complete revolution.

Please let me know if anyone knows about this.

Thanks
I've attached a sketch how to calculate the length of one bar.

You have to know the radius of the cylinder (if I read your drawing correctly $r_{eff} = 1'-6" = 18"$)

With a length of 45' and 16' per revolution you have to roll out and lay flat $\frac{45}{16}$ revolutions. Then the bar describes the diagonal of the rectangle.

3. Thanks a lot!. i really had no idea on how to solve this... thanks a lot again!