Opposite motion and an introduction to catch-up motion
Answers are for parents and teachers.
1
Two cyclists set out towards each other from places 108 km apart and met after 4 h. One rode at 12 km/h. How fast did the other ride (km/h)?
15
2
A walker (4 km/h) and a cyclist (12 km/h) set out towards each other from places 96 km apart. After how many hours do they meet?
6
3
Two ships sail from one pier in opposite directions at 20 and 30 km/h. How many km apart are they after 3 h?
150
4
A bus at 60 km/h is 30 km behind a car going 45 km/h. After how many hours does the bus catch up?
2
5
A boy runs at 5 m/s and a girl at 3 m/s; the girl is 18 m ahead. After how many seconds does the boy catch up?
9