(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 46.5 kg kid on roller blades pushes as hard as he can on a wall which causes him to start rolling away from the wall. At this point, friction begins to slow him down and he comes to rest 14.3 m from the wall. The coefficient of friction is 0.125. If his push lasted 0.460 s, how hard did he push on the wall (in Newtons)?

Rough diagram:

2. The attempt at a solution

J = Δ p

fΔt = mv_{2}- mv_{1}(mv_{2}= 0, since v_{2}is 0)

v_{1}= (F_{f}t)/(-46.5)

v_{1}= -0.563 m/s **

F_{f}= μF_{n}

=(0.125)(46.5)(9.8)

= 56.96N ( **I substituted this value to F_{f}in the (F_{f}t)/(-46.5) equation to find v_{1})

a = v_{2}- v_{1}(v_{2}= 0)

ta =0.563

0.460a= 1.225 m/s^{2}

F_{net}= ma

= (46.5)(1.225)

= 56.96N

Therefore, the average force exerted on the wall is 56.96N(BKWD)?

I tried doing this problem today but I feel that the answer is wrong(doesn't make sense) and that I made a mistake. Any help would greatly be appreciated :tongue:

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