A brother and sister walk home from school. After walking 500 m eastwards, the brother realises that he has left a book at school and he returns to school. His sister continues walking another 800 m to their home. She arrives home 30 minutes after leaving school.
2.1 Define the term average speed. (2)
2.2 Calculate the average speed of the girl from the school to her home. (4)
2.3 Use a vector scale diagram and represent the displacement of the boy from the time he realised he left his book at school until he reached home. Include ALL relevant information in the diagram.
Use scale 1 cm = 100 m for the diagram. (3)
2.4 If the average speed of the boy is the same as that of the girl, calculate how long it would take the boy to reach home from the time they both left the school together. (4)