# Calculate the Kinetic Frictional Force

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The alarm at a fire station rings and a 71.3-kg fireman, starting from rest, slides down a pole to the floor below (a distance of 3.63 m). Just before landing, his speed is 1.42 m/s. What is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole?

Givens:
m = 71.3 kg
d = 3.63 m
Vf = 1.42 m/s

d = Vf(t)/2
a = Vf/t
F = ma

3.63 m = 1.42 m/s (t) /2
7.26 m = 1.42 m/s (t)
t = 5.113 s

a =1.42 m/s /5.113 s
a = .278 m/s^2

F = 71.3 kg (.278 m/s^2)
F = 19.8 N

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The alarm at a fire station rings and a 71.3-kg fireman, starting from rest, slides down a pole to the floor below (a distance of 3.63 m). Just before landing, his speed is 1.42 m/s. What is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole?

Givens:
m = 71.3 kg
d = 3.63 m
Vf = 1.42 m/s

d = Vf(t)/2
a = Vf/t
F = ma

3.63 m = 1.42 m/s (t) /2
7.26 m = 1.42 m/s (t)
t = 5.113 s

a =1.42 m/s /5.113 s
a = .278 m/s^2

F = 71.3 kg (.278 m/s^2)
F = 19.8 N