Catch-up and delayed-start motion; unit review: number ray and motion
Answers are for parents and teachers.
1
A cyclist in front rides at 9 km/h and a walker 3 km behind walks at 5 km/h in the same direction. How many km apart are they after 2 h?
11
2
A walker left 2 h earlier at 5 km/h. A cyclist rides at 15 km/h. After how many hours does the cyclist catch up?
1
3
The gap is 50 km; the car behind goes 70 km/h and the one ahead 60 km/h. After how many hours does it catch up?
5
4
Two walkers leave one place in opposite directions at 4 and 5 km/h. How many km apart are they after 6 h?
54
5
The unit segment is e = 6 cm and the point is D(7). How many cm is OD?
42