Question

Rita jeptoo of kenya was the first female finisher in the 110th boston marathon. she ran the first 10.0 km in a time of 0.5689 h. assume the race course to be along a straight line. (a) what was her average speed during the first 10.0 km segment of the race? (b) she completed the entire race, a distance of 42.195 km, in a time of 2.3939 h. what was her average speed for the race?

Answer 1

Part a

Answer: 17.58 km/h

`Average speed=\frac{Total\hspace{1mm}Distance}{Total\hspace{1mm}Time}`

Total Distance =10 km

Total time =0.5689 h

`\Rightarrow Average speed=\frac{10\hspace{1mm}km}{0.5689\hspace{1mm}h}=17.6 \hspace{1mm}km/h`

Part b

Answer: 17.626 km/h

`Average speed=\frac{Total\hspace{1mm}Distance}{Total\hspace{1mm}Time}`

Total Distance =42.195 km

Total time =2.3939 h

`\Rightarrow Average speed=\frac{42.195\hspace{1mm}km}{2.3939\hspace{1mm}h}=17.626\hspace{1mm}km/h`