Why is it such hard work pumping up a bicycle tyre

Why is it such hard work pumping up a bicycle tyre  

The first law of thermodynamics states that energy may be converted between forms, but cannot be created or destroyed. Joule was a superb experimentalist, and performed various types of work, each time generating energy in the form of heat. In one set of experiments, for example, he rotated small paddles immersed in a water trough and noted the rise in temperature. This experiment was apparently performed publicly in St Anne s Square, Manchester. Joule discerned a relationship between energy and work (symbol w). We have to perform thermodynamic work to increase the pressure within the tyre. Such work is performed every time a system alters its volume against an opposing pressure or force, or alters the pressure of a system housed within a constant volume. 

The pressure inside a party balloon is higher than the external, atmospheric pressure, as evidenced by the way it whizzes around a room when punctured. 

Work is a form of energy. The word energy comes from the Greek en ergon, meaning from work.  

Work and energy can be considered as interchangeable we perform work whenever energy powers a physical process, e.g. to propel a car or raise a spoon to the mouth. The work done on a system increases its energy, so the value of U increases, itself causing A U to be positive). Work done by a system corresponds to a negative value of AU. 

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