**a) **Net work:

W_{net} = ΔKE

Also,

W_{net} = F•d = f_{k}•Δd = μ_{k}mgΔd

Equating:

μ_{k}mgΔd = KE_{i} - KE_{f}

μ_{k}mgΔd = (1/2)mv_{0}^{2} - (1/2)mv_{f}^{2}

Suppose that the coefficient of kinetic friction between Zak's feet and the floor, while wearing socks, is 0.250. Knowing this, Zak decides to get a running start and then slide across the floor.

a) If Zak's speed is 3.00 when he starts to slide, what distance will he slide before stopping? d=1.84

b) 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 over a distance of 1.00 . If her mass is 20.0 , what distance 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.

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