Margy is trying to improve her cardio endurance by performing an exercise in which she alternates walking and running 100.0 m each. If Margy is walking at 1.4 m/s and accelerates at 0.20 m/s2 during one of the running portions, what is her final velocity at the end of the 100.0 m? Round your answer to the nearest tenth.

In order to answer this excercise you need to use the formulas
s = Vot + (1/2)at^2
Vf = Vo + at
The data will be given as
Vf = final velocity = ?
Vo = initial velocity = 1.4 m/s
a = acceleration = 0.20 m/s^2
s = displacement = 100m
And now you do the following:
100 = 1.4t + (1/2)0.2*t^2
t = 25.388s
and
Vf = 1.4 + 0.2(25.388)
Vf = 6.5 m/s
So the answer you are looking for is 6.5 m/s

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MissPhiladelphia MissPhiladelphia · Answer 2 · 2017-01-07T22:47:39-05:00

Margy starts at 1.4 m/s
and accelerates 0.2 m/s^2 over a distance of 100.0m. The velocity over this time period will look like
v(t) = 1.4 + 0.2 t which tells you the velocity with respect to the time
the distance over this time. Another formula can also be used for this:
x(t) = Xi+Vit + 1/2at^2

Xi is the initial position taken to be 0 here

Vi is initial speed which is 1.4 m/s
a is 0.2 m/s^2
Total distance was 100
100= 0+1.4t + 1/2 0.2 t^2

Solve for t
and then
use the fact that
v=1.4+0.2t, to find the final velocity.