Recent content by lamina

Yep gauge is fine - if I use a straight steel bar instead of a pulley the force required goes way up to 7-10N. The mass is still when I measure the force to hold it, but I am moving it so gently that the gauge doesn't change much. Maybe I need a Video crew?

Hi, Doc Al. I have tried masses from 1 to 5N and angles from 10 to 90 to the vertical. The only time that I get a force which is not less than the mass being raised is if the wire does not touch the pulley. As soon as the wire starts to 'wrap' round the pulley then the force required to raise...

Three turns of tightly wrapped wire round the pulley - back to 4.5N.

Hi Shooting Star, I have wrapped the wire round the pulley twice and the 5N mass is lifted with a reading of 4.8N on the spring gauge. This is up from 4.5N with one turn. Tricky to do, but I will try to do three turns. Gee, I'm glad we haven't progressed beyond a single pulley :-))

Hi, I have attached a simple sketch of this simple set-up - The spring gauge is a good one and shows a zero reading when there is no force either horizontally or vertically Richard

As a matter of interest, this all started as a simple demonstration which I suggested to my wife, a seconday school teacher to show to her students. I am a Chartered Engineer, a member of the Institution of Mechanical Engineers, have a PhD in engineering and thought that a simple pulley would...

HallsofIvy - haha - I plan to make a larger version and hook it up to a generator - any idea where I can get a flux-capacitor - ebay are all out :-)) Richard

Hi, I can lift the 5N mass with a force of 4.5N when using the pulley - this force is the MAXimum reached when lifting and it gets nowhere near 5N - this can't be friction, this would increase the force required surely? Richard

Hi, Thanks for the replies. The setup is very simple. I have a plastic pulley wheel with steel supports. When the 5N mass is lifted vertically without the pulley in the system, the force measured on the spring gauge is 5N. If I put the wire round the pulley, the same mass requires 4.5N to...

Over Unity Efficient Pulley? Hi, I have a problem regarding a simple pulley system which seems to have an efficiency of over 100% and I just can't figure out what is going on. Scenario: I have a 5N mass vertically suspended using high tensile flexible steel wire from a simple spring gauge...