The displacement of a particle at time t s after leaving a fixed point O is s m. The diagram shows a displacement-time graph which models the motion of the particle. The graph consists of 4 straight line segments. The particle travels 50 m in the first 10 s, then travels at 2 m s⁻¹ for a period of 10 s. The particle then comes to rest for a period of 20 s, before returning to its starting point when t = 60. [Figure 1]

Mark scheme

Marking points from the official mark scheme (Feb/Mar 2024). The mark or mark type is shown in brackets.

1. [B1] Total distance travelled = 50+2×10 [= 70]
2. [B1FT] Velocity = -70/20 = -3.5 m s⁻¹ Oe. Ft their distance ≠50. Must be negative. Do not ISW if (e.g.) velocity = 3.5. Do allow "3.5 m s⁻¹, directed towards O.”
3. [B1] Velocity 5 ms⁻¹ for 0<t≤10. May be seen on diagram.
4. [B1] Stepped diagram with four horizontal lines segments. Ignore vertical line segments.
5. [B1FT] All correct. 10, 20, 40 and 60 indicated on the t-axis. Their 5, 2 and their –3.5 (allow -3 and -4 is acceptable too with line segment halfway between them) indicated on the v-axis, corresponding to the position of the horizontal line segments. FT their -3.5 ms⁻¹ and/or FT their 5 ms⁻¹. If their answer to (a) is positive, allow use of negative their answer for this mark.