Ok, so if an obect is picked up by holding it at the end of a 5 metre stick, then the object requires more force to lift, than at the end of a 1 metre stick, or with no stick at all. 1)Now I understand the Effect of this, What I don't understand is why this happens? The true mass of the object remains the same, but to me trying to lift it on a long stick it has a 'relative mass' which is far greater than its true mass. For the purposes of me lifting it, the object has gained a 'relative mass'. How can this be possible? What is physically taking place that causes this? It sound alot like getting something for nothing, and thats why i'm confused. 2)Does this 'relative mass' work for centrifugal force aswell? If a 10kg weight upon the end of a fixed arm 5 metres long were to spin at 1 rotation per second, how much force does the 10 kg weight contain, compared to the same apparatus but with a 3 metre arm? Is the difference in force, all explained by the larger circumference (thus greater acceleration)that the 5m arm must travel in the 1 second? Or would turning effect play apart aswell? As ever, a bit long winded, but i would really appreciate some feedback, thankyou.