An elevator is pulled vertically upwards by a cable. The elevator accelerates at 0.4ms⁻² for 5 s, then travels at constant speed for 25 s. The elevator then decelerates at 0.2m s⁻² until it comes to rest.

Mark scheme

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

1. [B1] Greatest speed = 2 [ms⁻¹] [0.4×5]. This can be seen on the graph and not stated explicitly.
2. [B1] Trapezium shape. Sitting on t-axis, starting at origin.
3. [B1] All correct including height of 2 and t-values of 5, 30, 40 on the horizontal axis. Labels not needed. Does not need to be to scale.
4. [M1] Distance = (1/2)(25+5+25+their 10)×their 2 or (1/2)×5×their 2 + 25×their 2 + (1/2)×their 10×their 2. Allow M1 for finding total area under their trapezium or appropriate 'suvat' in each phase. If presented as 3 areas, they do not need to be added for M1. Allow one wrong value but must represent all 3 phases of motion.
5. [A1] Distance = 65 [m].
6. [M1] Attempt at Newton's second law. Must have correct number of terms (5). Allow sign errors. Allow g missing. Use of a = g is M0A0A0 but condone use of a = 0.4 (from wrong phase).
7. [A1] 12250 - 1200g - mg = (1200+m)×(-0.2) Or 1200g + mg - 12250 = (1200+ m)×0.2. Correct equation. Note that taking a = 0.2 and omitting mg gets M0A0A0.
8. [A1] m = 50.
9. [M1] Realise that this is when accelerating and attempt Newton's second law for the crate only. Must have correct number of terms (3). Allow sign errors. Allow g missing. Must use a = ±0.4, M0A0A0 otherwise.
10. [A1FT] R - 50g = 50×0.4 or 50g – R = 50×(-0.4). Correct equation using their 50.
11. [A1] Force R = 520 [N], upwards. Must include 'upwards' OE.