A particle of mass 1.6kg is dropped from a height of 9 m above horizontal ground. The speed of the particle at the instant before hitting the ground is 12ms¯¹.

Mark scheme

Marking points from the official mark scheme (May/June 2023). The mark or mark type is shown in brackets.

1. 12² = 2 × 9 × a. OR a=8.
2. [M1] Use of suvat to get an equation in a.
3. 1.6g - R=1.6a.
4. [M1] Use Newton's second law with 3 terms, allow sign errors. Allow their a ≠ g. Allow a if it isn't subsequently replaced with g.
5. WD [= 3.2×9] = 28.8 J
6. [A1]
7. Alternative method for Question 1
8. (KE =) ½×1.6×12² OR 115.2
9. [B1] Allow for the expression for KE.
10. (Loss of PE =) ±1.6g×9 OR ±144
11. [B1] Allow for the expression for PE.
12. WD = 28.8 J
13. [B1] Allow if get –28.8 and then say 28.8 without explanation. Do not allow -28.8 as final answer to working, so if get 28.8 and state -28.8 then ISW.