PHYSICS · Multi-part · GCSE · Physics · Energy · Energy
Problem
Answer the questions given below.
(i) Starting from the definition of work done against gravity, derive an expression for the gravitational potential energy of a body of mass m raised through a vertical height h near the Earth’s surface.
(ii) A ball of mass 0.8kg lies at the bottom of a dry pit that is 3.0m below ground level. The ball is lifted to a platform 2.0m above ground level. Using g=9.8m s−2, calculate the work done in (a) bringing the ball from the pit bottom to ground level, (b) raising the ball from ground level to the platform, and (c) the entire process.
(iii) Would the total work done be different if the ball were lifted directly from the pit bottom to the platform in a single step instead of two separate steps? Give a reason for your answer.