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Barry walks from one end to the other of a 30-meter long moving walkway at a constant rate in 30 seconds, assisted by the walkway. When he reaches the end, he reverses direction and continue walking with the same speed, but this time it takes him 120 seconds because he is traveling against the direction of the moving walkway. If the walkway were to stop moving, how many seconds would it take Barry to walk from one end of the walkway to the other

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FaridRjb

Answer:

Δt=48 s

Explanation:

v: Barry's speed

v.: speed of the walkway

Δx=30 m

Δt1=30 s ,  Δt2=120 s

|Δx1|=|Δx2|

Δx=v*Δt

=> (v+v.)*30=(v-v.)*120

v=v.*5/3

30=(v+v.)*30

=> 30=(5v./3 +v.)*30

v.=3/8 m/s

v=5v./3 , v.=3/8

=> v=5/8 m/s

Δx=v*Δt

30=5/8 *Δt

Δt=48 s

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