Answer:
1). Average speed = 1.5 m per second
2). Average velocity = 1.5 m per second
Explanation:
1). Since, speed is a scalar quantity
Therefore, average speed of the trip = 
From the graph attached,
Total distance covered = 10 + 10 + 20 + 0 + 20 + 30
= 90 meters
Total time taken = 60 seconds
Average speed = 
= 1.5 meter per second
2). Velocity is a vector quantity.
Therefore, average velocity = 
= 
= 
= 1.5 meter per second
I think it would be warmer in a grassy field with no wind on a winter day because you'll have sunlight hitting you. However, if you were in a thick forest, all sunlight would be blocked and you would have no warmth from the sun.
Galileo is geocentric, just like all the rest of us.
Steel materials produce less vibrations whilst less dense and more malleable parts produce more vibrations, e.g. the wooden part of the coaster itself.