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9th CBSE
IMPORTANT
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A block of wood can float while a similar sized block of concrete can be used as an anchor. Why?

Important Questions on Gravitation

MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>CHAPTER EXERCISE>Q 25
How does the force of attraction between the two bodies depend upon their masses and distance between them? A student thought that two bricks tied together would fall faster than a single one under the action of gravity. Do you agree with his hypothesis or not? Comment.
MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 1
If a satellite is revolving around a planet of mass M in an elliptical orbit of semi-major axis a, find the orbital speed of the satellite when it is at a distance  r from the focus.
MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 2

Distance between the centres of two stars is 10 a. The masses of these stars are M and 16 M and their radii are a and 2 a respectively. A body of mass m is fired straight from the surface of the larger star towards the smaller star. The minimum initial speed for the body to reach the surface of the smaller star is _____.

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MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 3
A satellite is launched in a circular orbit of radius R. Another satellite is also launched in an orbit of radius 1.1 R. The period of the second satellite is larger than the first by approximately.
MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 4

If earth comes closer to sun by 3/4 th of the present distance, then the year of the earth consists of how many days?

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MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 5
Communication satellites move in orbits of the radius of 44400 km around the earth. Assume that the only force acting on it is that due to the earth, then what is the acceleration of such a satellite? (Take, the mass of earth=6×1024kg)
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9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 6
The mean radius of the Earth's orbit around the sun is 1.5×1011 m. The mean radius of the orbit of Mercury around the sun is 6×1010 m. The Mercury will rotate around the sun in _____.
MEDIUM
9th CBSE
IMPORTANT
All In One SCIENCE CBSE Class IX>Chapter 10 - Gravitation>Challengers*>Q 7
A tank of 5 m high is filled with water and then is filled to the top with oil of density 0.85 g/cm3. The pressure at the bottom of the tank, due to these liquids is _____.