Foundation November 2018 Paper 3 Q20
20 A bee flies from its hive to a flower at a constant speed of 7.5 metres per second for 10 seconds.
The bee then takes 15 seconds to fly back to the hive.
Assume the bee always flies in a straight line.
(a) Ignoring the time spent at the flower, work out the overall average speed of the bee in its flight from the hive to the flower and back. [4]
(b) If the bee is not assumed to fly in a straight line, how might your answer be affected? [1]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 6 | 4 | M3 for \(\dfrac{2 \times 7.5 \times 10}{10 + 15}\) or M2 for speed = distance ÷ time correctly applied or M1 for 7.5 \(\times\) 10 soi 75 or If 0 scored SC2 for answer 6.25 | May be in stages: 7.5 \(\times\) 10 = 75 → 75 \(\times\) 2 = 150 → 10 + 15 = 25 → 150 \(\div\) 25 [= 6] Mark overall process ignoring numerical errors Distances: 75, 150, 112.5, 187.5 m Times: 10, 20, 15, 25 s |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| [Average] speed [may be] greater oe | 1 | Time is longer ... scores 0 Mark the best bit unless contradictory. E.g. It might have gone faster or slower. Do not accept “It (or distance) will be longer”. Must go on to say “so the bee flies faster” oe Condone “It will be bigger” | |