Complete Question
The complete question is shown on the first uploaded image
Answer:
The velocity is in positive x -direction
The speed is
Explanation:
From the question we are told that
The distance from the house to truck is D = 20 m
The distance traveled back to retrieve wind-blown hat is d = 15
The distance from the wind-blown hat position too the truck is k = 20 m
The total time taken is t = 75 s
Generally when calculating the displacement the Justin's backward movement to collect his wind - blown hat is taken as negative
Generally Justin's displacement is mathematically represented as
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Generally the average velocity is mathematically represented as
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Generally the distance covered by Justin is mathematically represented as
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Generally Justin's average speed over a 75 s period is mathematically represented as
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Answer
given,
cooling fan revolution = 850 rev/min
fan turns before revolution = 1500 revolutions
θ = 1500 revolution
θ = 1500 x 2 x π
θ = 9424.78 rad
a) using equation of rotation
ω² = ω₀² + 2 α θ
ω = 0 because body comes to rest
0 = 89² + 2 x α x 9424.78
α = -0.42 rad/s²
b) time take for the fan to stop
ω = ω₀ + α t
0 = 89 - 0.42 t
t = 211.9 s