Rattigan_Roger question..

[wyliec]

This may seem like a strange question; but, here it goes...

If you have a 6' long (barbell) bar that weighs 45# and one end is placed in a swivel/pivot holder and you lift the opposite end are you lifting 45#? The end in the pivot/swivel is about 8" and doesn't leave the floor. This isn't a trick question; I'm just trying to determine how much I've been lifting.

 

[warp10]

nope, you have not lifted the entire bar, just your end of it. get a fish scale and lift the bar end with that and see how much it says.

 

[spydaman60]

nope, you have not lifted the entire bar, just your end of it. get a fish scale and lift the bar end with that and see how much it says.

:agree: i would think it should be 1/2 or 22.5 pounds!

 

[Ga Blue Knight]

Actually the weight lifted varies by the angle to the fulcrum. It start out as heavy and then gets lighter as the angle approaches 90 degrees. I used to know the formular but now that I am old it is in my brains delete file.

 

[Jeriatric]

[h=3]Example - First-Class (Order) Lever - A force (weight) of 1 pound is exerted at the end of a lever at distance 1 ft from the fulcrum[/h]The effort force at a distance of 2 ft from the fulcrum can be calculated as

F[SUB]e[/SUB] = (1 lb) (1 ft) / (2 ft) = 0.5 (lb)
​

The formula (1) can be modified to express required load if you know the effort, or required distance from fulcrum if load and effort forces are known and so on.

The level above where the fulcrum located between the load and effort force is often characterized as a first-class level mechanism.

A level where the load and effort force are located on the same side of the fulcrum is often characterized as a second-class level mechanism.

 

[wyliec]

nope, you have not lifted the entire bar, just your end of it. get a fish scale and lift the bar end with that and see how much it says.

You've actually lifted (almost) the entire bar, just not to the same height. I like the idea of the fish scale as it seems to be the easiest way to get a ball park figure.


It may be a moot point since I just made one of these to do 'squats'.

http://www.instructables.com/id/How-to-make-a-loading-pin/

 

[Bob Denman]

Holy Christmas! :shocked:

 

[Jeriatric]

You've actually lifted (almost) the entire bar, just not to the same height. I like the idea of the fish scale as it seems to be the easiest way to get a ball park figure.


It may be a moot point since I just made one of these to do 'squats'.

http://www.instructables.com/id/How-to-make-a-loading-pin/

FWIW - If you want to do a KILLER squat that requires 0 weight. I highly recommend the "Frog squat".

Do some research on the instructor and you'll find him very reputable.

 

[Bob Denman]

:shocked: :thumbup: :roflblack:
I'm so ashamed...:shocked:

 

[wyliec]

Jerbear

Example - First-Class (Order) Lever - A force (weight) of 1 pound is exerted at the end of a lever at distance 1 ft from the fulcrum

The effort force at a distance of 2 ft from the fulcrum can be calculated as

F[SUB]e[/SUB] = (1 lb) (1 ft) / (2 ft) = 0.5 (lb)
​

The formula (1) can be modified to express required load if you know the effort, or required distance from fulcrum if load and effort forces are known and so on.

The level above where the fulcrum located between the load and effort force is often characterized as a first-class level mechanism.

A level where the load and effort force are located on the same side of the fulcrum is often characterized as a second-class level mechanism.

Your diagram is a little off. The fulcrum is okay; but, there are weights (the load) placed at the opposite end and I am lifting (effort force) just to the back side of the weights (my hands are between the fulcrum and weights, so to speak).

 

[Bob Denman]

:shocked: But the pancakes don't add up... :shocked:
I need more coffee and a nap if there's gonna be a test like this at the end of class every day! :gaah:

Wylie,
Why are we doing this? (If it's okay to ask...)

 

[wyliec]

:shocked: But the pancakes don't add up... :shocked:
I need more coffee and a nap if there's gonna be a test like this at the end of class every day! :gaah:

Wylie,
Why are we doing this? (If it's okay to ask...)

Bob,

Since you asked:

I have an ironmind hip belt shown here:

However, I decided to hook it up to a T-bar shown here:

So, instead of using my upper body with the T-bar (as shown in the above video), I connect the hip belt and do squats for my legs (that you poked fun at in one of my previous posts).

But, getting back to your question, I know how much weight I have at the end of the bar; I was just trying to figure out how much to add for the barbell bar.

 

[Bob Denman]

I poked fun at your legs??? :shocked: I can't imagine doing that because of the shape that mine AREN'T in... nojoke
But that sure looks like work; :yikes: Something that I've become allergic to in recent years...
I've become so weak that even picking up a check will leave me winded! :roflblack: