The questions are on the average speed test. Take it under real conditions before reading the mark scheme.
Quick answer: Average speed is the total distance an object travels divided by the total time it takes, written v = d ÷ t. This mark scheme gives the model answers and the marks for the 9 questions of the grade 6 science test on average speed, from key words to SI unit, with the equivalent answers to accept.
Model answers and mark allocations are given for every question. Award marks for correct method even when an arithmetic slip leads to a wrong final value, and check that each answer has the correct unit.
Level: Grade 6 science (Year 7 · Class 6) · Curriculum: MS-PS2-2
Question 1 Key words (2 marks)
A reference object is an object treated as fixed and used to decide whether another object moves. A trajectory is the path followed by a moving object.Marking: 1 mark for each correct definition.
Question 2 Ferry crossing (2 marks)
v = d ÷ t = 15 ÷ 0.75 = 20 km/h.Marking: 1 mark for the formula and substitution, 1 mark for the answer with unit.
Question 3 Unit change (2 marks)
144 ÷ 3.6 = 40 m/s.Marking: 1 mark for dividing by 3.6, 1 mark for the answer with unit.
Question 4 Tram graph (4 marks)
- It is at rest (the line is horizontal at 40 m).
- v = 40 ÷ 20 = 2 m/s.
- v = (100 − 40) ÷ 20 = 3 m/s.
- v = 100 ÷ 60 = 1.7 m/s (1.67 m/s).
Marking: 1 mark for each part.
Question 5 Marathon pace (2 marks)
t = 20 × 60 = 1200 s. d = v × t = 5.5 × 1200 = 6600 m (6.6 km).Marking: 1 mark for converting the time, 1 mark for the answer with unit.
Question 6 Moving or not? (3 marks)
Relative to her seat, the passenger does not change position, so she is at rest. Relative to the ground below, her position changes by 250 m every second, so she moves at 250 m/s. Rest and motion depend on the reference object.Marking: 1 mark for rest relative to the seat, 1 mark for moving relative to the ground, 1 mark for linking this to the choice of reference object.
Question 7 Faster or slower? (2 marks)
30 m/s × 3.6 = 108 km/h, which is greater than 90 km/h. Bilal is wrong: the car at 30 m/s is faster.Marking: 1 mark for converting to common units, 1 mark for the correct conclusion.
Question 8 Freight train (2 marks)
t = d ÷ v = 450 ÷ 75 = 6 h.Marking: 1 mark for the formula and substitution, 1 mark for the answer with unit.
Question 9 SI unit (1 mark)
The metre per second, m/s.Marking: 1 mark.
