Question

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.

Answer 1

In order to answer this exercise you need to use the formulas

 S = Vo*t + (1/2)*a*t^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

Answer 2

Answer:

$v_f = 6.48 m/s$

Explanation:

As we know that her speed while she walk is given as

$v_o = 1.4 m/s$

now here acceleration is given as

$a = 0.20 m/s^2$

now the distance moved by her

$d = 100 m$

now the final speed is given as

$v_f^2 - v_0^2 = 2 a d$

so we have

$v_f^2 - 1.4^2 = 2(0.20)(100)$

$v_f = 6.48 m/s$