Answer: B) 2.5 m/s
Explanation: Find the average of the time and distance, and see how far they go in only 1 second.
1 + 2 + 3 + 4 + 5 = 15
15 divided by 5 = 3
3 seconds
2 + 5 + 7 + 10 + 12 = 36
36 divided by 5 = 7.2
7.2m per 3 seconds.
7.2 divided by 3 = 2.4
Therefore, the answer is technically 2.4m/s
Question 2 is because the passengers have inertia, which is a tendency to resist change in motion
This suggest the the atom has a very small positively charged nucleus in the mass of the atom is concentrated.
And the electrons revolves around the nucleus in their orbits.
I can't guess what -9.8 m/s means until you tell me where it came from,
or what 'm/s' means.
If perhaps it has something to do with the acceleration of gravity on Earth,
then the correct figure is ' -9.8 m/s² '. That means that any object that
has no other force acting on it except gravity has its speed changing by
9.8 meters per second every second. Since it's gravity doing the job,
then the object's speed is either increasing down, or decreasing up.
If an object has negative velocity, then it's moving in the direction opposite
to the direction that you decided to call positive when you started doing the
problem.
For example, if you decide that up is positive and down is negative, and
then somebody drops a stone from the top of a tall building, then the
gravitational force on the stone is negative (pointing down), its velocity
is negative (it's falling towards down), and its acceleration is negative (its
speed towards down is getting faster and faster). Everything is negative,
only because you decided that up is positive and down is negative. It's
nothing to be worried about.