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Assertion: Aeroplanes are made to run on...

Assertion: Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift.
Reason: This is as per Bernoulli's theroem.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
A
Usually the air does not strike the wring of the aeroplane with large velocity. To get the lift, the aeroplane runs for some distances on the runways before taking off. Due to the special shape of wrings, the velocity of the layers of air above the wings increase (becomes layers came near each other) and hence pressure decreases. Due to this aeroplane gets uplift.
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Knowledge Check

  • Assertion : Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift. Reason : According to Bernoulli's theorem, as velocity increases pressure decreases and viceversa.

    A
    If both assertion and reason are true and the reason is the correct explanation of the assertion.
    B
    If both assertion and reason are true and the reason is not the correct explanation of the assertion.
    C
    If assertion ture but reason is false.
    D
    If the assertion and reason both are false.

  • Assertion : Sometimes a crackling sound is heard while taking off sweater during winters. Reason : The electric discharge takes place between body and sweater.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion.
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion.
    C
    If assertion is true but reason is false.
    D
    If assertion is false but reason is true.

  • given passage carefully and answer the questions that follow by selecting the most appropriate option. Helicopters are very different from airplanes. They can do three things that airplanes cannot do. First, when airplanes move upward, they must also move forward, but helicopters can move straight up without moving ahead. Second, helicopters can fly backward, which airplanes cannot do. Third, helicopters can use their rotors to hover in the air, which is impossible for airplanes. Helicopters can perform actions that airplanes cannot, they are used for different tasks. Since, helicopters can take off without moving forward, they do not need a runway for take off. They are used in congested areas where there is no room for airplanes or in isolated areas, which do not have airports. Because they can hover, they are used on firefighting missions to drop water on fires. They are used in logging operations to lift trees out of forests. Helicopters are used as air ambulances to airlift patients out of situations, which are difficult to reach by conventional ambulances. The police used helicopters to follows suspects on the ground or to search for cars on the ground. Of course, helicopters have military uses because of their design and capabilities. The word 'congested in the passage means

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    C
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    D
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