Please see attached images. Those pencil-written answers are directly copied from marking scheme (after using considerable amount of time calculating and still getting the wrong answer) 1. For question 1, why is the weight taken as 3.8N regardless of the additional force F? 2. In question 1, gravitational potential energy is supposed to be lost because the height of the object from the ground has decreased. Then why is the answer not negative? 3. For question 3, why is it just Es - Ep? Combining with my second question, is it because the F caused a decrease in gravitational potential energy, and caused an increase in elastic potential energy at the same time?