Two pendulums of length 1 m and 16 m start vibrating one behind the ot...
T1=2π√1/g=T, T2=2π√16/g=4T
(ω1−ω2)t=2π
(2π/T−2π/4T)t=2π
t=4T/3
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Two pendulums of length 1 m and 16 m start vibrating one behind the ot...
Solution:
Given, length of shorter pendulum, l₁ = 1 m
and length of longer pendulum, l₂ = 16 m
Let the time period of shorter pendulum be T
The time period of a simple pendulum is given by the formula,
T = 2π √(l/g) where l is the length of the pendulum and g is the acceleration due to gravity.
Therefore, time period of shorter pendulum, T = 2π √(1/g) ...(1)
and time period of longer pendulum, T' = 2π √(16/g) = 8π √(1/g) ...(2)
Let the shorter pendulum complete n oscillations before the longer pendulum completes one oscillation.
In n time periods of the shorter pendulum, the angle covered by it is θ₁ = 2π n
In the same time period, the angle covered by the longer pendulum is θ₂ = 2π (n/16)
When the two pendulums are in the mean position and in the same phase, the angle between them is zero.
To bring both the pendulums back in the same phase, the shorter pendulum must complete one more oscillation than the longer pendulum.
So, we can equate the angles covered by both pendulums as follows:
θ₁ - θ₂ = 2π
=> 2π n - 2π (n/16) = 2π
=> 2π (15n/16) = 2π
=> n = 16/15
The time taken for the shorter pendulum to complete 16/15 oscillations is given by
t = (16/15) × T = 16T/15
The time taken for the longer pendulum to complete one oscillation is given by
t' = T'
The minimum time after which two pendulums will be one behind the other is the time taken by the longer pendulum to complete (16/15) oscillations which is given by
t' × (16/15) = (8π/15)√(1/g) × (16/15) = (32/15)π√(1/g)
From equation (1), we know that T = 2π √(1/g)
So, (32/15)π√(1/g) = (64/15)T = 4T/3
Therefore, the correct answer is option (d) 4T/3.