Question

Now, suppose that Zak's younger cousin, Greta, sees him sliding and takes off her shoes so that she can slide as well (assume her socks have the same coefficient of kinetic friction as Zak's). Instead of getting a running start, she asks Zak to give her a push. So, Zak pushes her with a force of 125 N over a distance of 1.00 m. If her mass is 20.0 kg, what distance d2 does she slide after Zak's push ends? Remember that the frictional force acts on Greta during Zak's push and while she is sliding after the push.

Answer 1

Answer:  1.55 m

Explanation:

from the question we were given

force = 125 N

distance = 1 m

mass = 20 kg

first we find the work done in pushing her = force x distance

   work done = 125 x 1 = 125 j

now we find the frictional force = (  coefficient of friction x mass x acceleration due to gravity ), taking the coefficient of friction as o.25 and acceleration due to gravity as 9.8 m/s

frictional force = 0.25 x 20 x 9.8 = 49 N

the frictional force must do the same amount of work Zak did in pushing his sister so as to bring her to a stop. now we can get the distance she slides by applying the formula work done = frictional force x distance

  125 = 49 x distance

distance = 125 / 45 = 2.55 m

to get how far she slides after Zak's push stops we have to subtract the distance she was pushed for from the total distance she slid

= 2.55 - 1 = 1.55 m