Read the assertion and reason carefully to mark the correct option ou...
If a pendulum is suspended in a lift and lift is moving downward with some acceleration a, then time period of pendulum is given by,
In the case of free fall, a=g then T=∞ i.e The time period of the pendulum becomes infinite.
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Read the assertion and reason carefully to mark the correct option ou...
Assertion: If a pendulum is suspended in a lift and the lift is falling freely, then its time period becomes infinite.
Reason: A free-falling body has an acceleration equal to the acceleration due to gravity.
Correct Answer: Option A - If both the assertion and reason are true and the reason is the correct explanation of the assertion.
Explanation:
The time period of a pendulum is the time taken for it to complete one full swing back and forth. It depends on the length of the pendulum and the acceleration due to gravity.
In this scenario, when the lift is falling freely, the entire system (the pendulum and the lift) is in a state of free fall. In free fall, the acceleration experienced by all the objects is equal to the acceleration due to gravity, regardless of their masses.
Let's analyze the assertion and reason in detail:
Assertion: If a pendulum is suspended in a lift and the lift is falling freely, then its time period becomes infinite.
When the lift is falling freely, the pendulum and the lift are both accelerating downwards with the same acceleration. The pendulum will continue to swing back and forth due to its inertia, but the effective acceleration acting on it is zero. This is because the acceleration due to gravity is canceled out by the acceleration of the lift. As a result, the time period of the pendulum becomes infinite. This means that the pendulum takes an infinitely long time to complete one swing back and forth.
Reason: A free-falling body has an acceleration equal to the acceleration due to gravity.
This reason is correct. When an object is in a state of free fall, it experiences an acceleration equal to the acceleration due to gravity. This can be explained by the fact that the only force acting on the object is the gravitational force, which causes it to accelerate downwards.
Conclusion:
Therefore, the assertion and reason are both true, and the reason correctly explains the assertion. When a pendulum is suspended in a lift that is falling freely, its time period becomes infinite because both the pendulum and the lift are accelerating downwards with the same acceleration due to gravity.
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