recall and use W = pΔV for the work done when the volume of a gas changes at constant pressure and understand the difference between the work done by the gas and the work done on the gas

understand the concept of work, and recall and use work done = force × displacement in the direction of the force

describe and use the concept of weight as the effect of a gravitational field on a mass and recall that the weight of an object is equal to the product of its mass and the acceleration of free fall