146. The escape velocity of a particle of mass m varies as

1. 1. m°

   
   
   

   2. m

   
   
   

   3. m²

   
   
   

   4. m^-1

   
   
   

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   Correct Option: A

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147. A person is sitting in a moving train and is facing the engine. He tosses up a coin and the coin falls behind him. It can be concluded that the train is moving

1. 1. Forward and losing speed

   
   
   

   2. Forward and gaining speed

   
   
   

   3. Forward with uniform speed

   
   
   

   4. Backward with uniform speed

   
   
   

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   Correct Option: B

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148. Which of the following statements is false?

1. 1. The magnitude of a vector is always a scalars

   
   
   

   2. The total path length is always equal to the magnitude of the displacement vector of a particle

   
   
   

   3. The average speed of a particle is either greater or equal to the magnitude of the average velocity of the particle over the same interval of time

   
   
   

   4. Three vectors not lying in a plane can never add up to give a null vector

   
   
   

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   Correct Option: B

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149. Bernoulli's principle does not explain

1. 1. Curved path of a spinning ball

   
   
   

   2. Lift of a jet

   
   
   

   3. Working of a paint sprayer

   
   
   

   4. Automatic blowing of the roofs of houses during blizzard in hilly areas.

   
   
   

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   Correct Option: B

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150. A ball is dropped from a spacecraft revolving around the earth. It will

1. 1. Continue to move with the same speed along the original orbit of the space craft

   
   
   

   2. Move with the same speed tangentially to the orbit

   
   
   

   3. Fall down to the earth

   
   
   

   4. Move away from the earth

   
   
   

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   Correct Option: A

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