Aperson walks first at a constant speed of 4.90 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.90m/s.
(a) what is her average speed over the entire trip? (in m/s)

The person's average speed over the entire trip was 3.9 m/s.

Explanation:

The average speed over the trip was:

s = (s₁ + s₂) / n = (4.9 m/s + 2.9 m/s) / 2 = 3.9 m/s

s: speed of the entire trip

s₁: speed in 1° section of the trip

s₂: speed in 2° section of the trip

n: number of sections

The important thing is the speed of the person walking but not the distance travelled during the trip.

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