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Q:

When a steel ball is placed on the surface of mercury, it does not sink because

A) of the surface tension of mercury B) mercury is a semisolid
C) of the high viscosity of mercury D) the density of mercury is greater than that of steel
 
Answer & Explanation Answer: D) the density of mercury is greater than that of steel

Explanation:

A solid sinks in a liquid if its density is greater than that of the liquid. if less, it floats

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Q:

The force that keeps a body in a circular motion called 

A) the centripetal force B) the centrifugual force
C) the frictional force D) all the above
 
Answer & Explanation Answer: A) the centripetal force

Explanation:

without this centripetal force, circular motion is not possible. It acts radially towards the centre and if this force is removed there will be no circular motion but the revolving body will fly off at a tangent.

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Q:

When a bullet is fired from a gun 

A) the gun moves forward B) the gun jumps up
C) the gun does not move D) the gun recoils with the same momentum as the bullet
 
Answer & Explanation Answer: D) the gun recoils with the same momentum as the bullet

Explanation:

Newton's III law involved

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Q:

A boy is swinging a ball attached to a string in a horizotal circle. If the string snaps 

A) the ball will travel towards the center of the circle and fall down B) it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down
C) it will fall down at the same place where the string breaks D) None of these
 
Answer & Explanation Answer: B) it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down

Explanation:

The centripetal force having been removed the body cannot  execute the curved path

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Q:

What is the minimum velocity required for a rocket to overcome earth's gravity and travel into space?

A) 18 km/sec B) 11.2 km/sec
C) 21 km/sec D) 35 km/sec
 
Answer & Explanation Answer: B) 11.2 km/sec

Explanation:

This 11.2 km/s is also known as the escape velocity. It works out to roughly 25000miles per hour 

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Q:

A hunter on the ground wishes to shoot a  bird on a tree at a distance with his rifle. He has to point the rifle

A) at the lower alevation than the bird B) at a higher alevation than the bird
C) In the same direction as the bird D) vertically upwards
 
Answer & Explanation Answer: B) at a higher alevation than the bird

Explanation:

The trajectory of the bullet is a parabola

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Q:

The playback singer who is certified as the 'Most Recorded Artist' in the world (2009) by the World Records Academy is ________

Answer

Asha Bhosle . She  is the sister of Latha Mangeshkar

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Q:

Who is the co-founder of Hotmail?

Answer

Sabeer Bhatia

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