Answer:
t = (t₁ · vr)/ (vj - vr) = 45 seconds
Step-by-step explanation:
Given:
Initial time from Ricardo t₁ = 15 seconds, Ricardo's velocity (speed) vr = 3 ft/s,
John's velocity (speed) vj = 4 ft/s
Requested time when John catch Ricardo t = ?
During 15 seconds, Ricardo moved away
S = vr · t₁ = 3 ft/s · 15 s = 45 feet.
From that moment, the same time runs for both of them
Ricardo's path is S₁ = vr · t and John's path is S₂ = vj · t
S + S₁ = S₂ => S = S₂ - S₁ => 45 = vj · t - vr · t
When we draw t we get:
t ( vj - vr) = 45 t = 45 / (vj - vr) = 45 / (4 - 3) = 45 / 1 = 45 seconds
t = 45 seconds
S₁ = vr · t = 3 · 45 = 135 ft
S₂ = vj · t = 4 · 45 = 180 ft
God with you!!!
