Q1. Sue pumps up a bicycle tyre. As she does so, she notices that the pump becomes hot.
(a) Where, and how, was the energy stored before it was transferred in pumping up the tyre?

The energy was stored as chemical energy in Sue' muscle before it was transformed into mechanical energy that moves the pump handle to ump the tyre

Explanation:

In pumping up the tyre, the valve of manual pump is attached airtight to the tyre tube

As the handle of the pump is pulled up or out, air rushes into the pump from the atmosphere through the inlet valve

As the handle pushed in, the inlet valve closes and the air is forced into the tyre tube by difference in pressure and as the tube is filled, more pressure is required to enable the tube expand and build pressure inside to maintain a circular cross section while carrying load

According to Gay Lussac's Law, temperature of the air in the pump increases as its pressure increases

Given that Sue provides the energy for pumping the tyre, the energy was stored as chemical energy in Sue's muscles which is then used in moving the pump handle in the up and down motion required to pump the tyre

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.

+15-35=-20

going in opposite directions