Answer:
a.52.9 km/h
b.90 km
Explanation:
We are given that






Time spend on eating lunch and buying ga=15 min.
a.Total time=30+12+45+15=102 minute=
1 hour=60 minutes
Distance=



Total distance=
Average speed=
Using the formula
Average speed=
b.Total distance between the initial and final city lies along the route=90 km
The formula of the kinetic energy is:

where m is a mass of the object, v is speed of the object at the moment of time. So we have:

The answer is
2000 Joules.
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