When light travels from air into water,it slows down,causing it to change directions slightly
Answer:
A horizontal line on a speed-time graph represents a constant speed. A sloping line on a speed-time graph represents an acceleration. The sloping line shows that the speed of the object is changing. The object is either speeding up or slowing down.
Becky's speed is her distance travelled which is 30 km divided by her time travelled of 2.5 hours which gives her average speed of 12 km/hour which is a quite good speed if she was say riding a bicycle and which would give her a good aerobic workout.