Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 2016-01-06 13:55:14

Barry Parkinson
Guest

Shear of 8mm bolt is 1500kg BUT??? see my question

I have conflicting answers to my question from the manufactures.

I have been told the SHEAR of the item I want to buy is dependent on the angle of the rope(sheet) passing through the Deck Organizer block which is true but, I can't check out the answers I have been given by the Mfg of the block, even though I have been given the Formula and 4 answers.

The Formula I have has Sine and maybe Radian, I say maybe because in one Formula 'Radian' is left out.

The task is to determine what the Safe Working Load of a Yacht Deck rope Organizer block is:- I am told 1500kg is the S.W.Load therefore the Formula is 1500/(*2SIN(RADIANS(20)/2)) = 4319.078kg - I don't get this answer because my Formula is wrong.

I have also been told the Formuls is:- 1500/(20/2 SIN) x 2) = 4320kg (NO MENTION of RANIAN in the Formula)

Can you help???

Rope angle into block 20deg = 4319kg, 30deg = 2897kg, 45deg = 1959kg, and so on for 60deg = 1250kg I am told.

#2 2016-01-06 17:56:59

Relentless
Member
Registered: 2015-12-15
Posts: 631

Re: Shear of 8mm bolt is 1500kg BUT??? see my question

Hi; The second formula is correct; there are no radians here, only degrees.

The formula you want is

which can also be written as

Whoever told you the first formula must have just been confused about their units. If you use radians you get crazy answers like minus 1400kg.

Edit: I have checked that this same formula works for all the other angles you mentioned and answers you expect, except I think that 60 degrees should be 1500kg (1250kg is at about 73 degrees). Remember, all angles are in degrees - we are not working with radians!

Just plug the angle you want into this formula, where the angle is x:

Or:


As you have it:

They will all do the trick.
I hope that's clearer (:

Last edited by Relentless (2016-01-06 18:22:48)

Offline

Board footer

Powered by FluxBB