Calculating work and energy - Higher
Force exerted over an area. The greater the pressure, the greater the force exerted over the same area. can be increased by:
- increasing the A measure of the average kinetic energy of particles in a substance. - this increases the freqency and A push or a pull. The unit of force is the newton (N). of collisions
- decreasing the The volume of a three-dimensional shape is a measure of the amount of space or capacity it occupies, eg an average can of fizzy drink has a volume of 330 ml. - this increases the frequency of collisions but not the force
A force applied to the particles in a gas causes a transfer of The capacity for doing work..
When a person presses a piston down on a column of gas, they apply a A push or a pull. The unit of force is the newton (N). to move the piston a certain distance.
Energy transferred by a force. Work done = force 脳 distance moved in the direction of the force. is done on the gas to compress it:
work done (J) = force (N) 脳 distance (m)
The volume of the gas decreases so the pressure increases. This is because the gas A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. are moving in less space, so they collide with the container walls more often.
The temperature of the gas is not fixed in most applications, and the increased pressure leads to an increase in temperature. Temperature is a measure of the average Energy which an object possesses by being in motion. of particles, so an increase in the energy store of the gas (as kinetic energy of the particles) means that the temperature must increase.
This process explains why a bicycle pump gets warm when it is used to inflate a tyre.