# 29 - Gravitation Questions Answers

The gravitational field in a region is given by :

E= 5 N/ kg i 12 N/ kg J

If the potential at the origin is taken to be zero,

then the ratio of the potential at the points (12m, 0) and (0, 5m) is ??

**Asked By: PADMA**2 year ago

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a large number of identical point masses m are placed along x-axis , at x=0,1,2,3,4.....the magnitude of gravitational force on mass at origin (x=0), will be ??

**Asked By: RUDRIK S PATEL**2 year ago

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A lift ascends from rest with uniform acceleration of 4m/s^2, then it moves with uniform velocity and finally comes to rest with uniform retardation of 4m/s^2. If the total distance covered during ascending is 28m and total time taken for ascending is 8s respectively. Find the time for which the lift moves with uniform velocity .Also find its uniform Velocity.

**Asked By: EZHILARASAN**3 year ago

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Disatnce b/w center of 2 stars is 10a. masses are M and 10M and radii rae A ans 2A ,resp. a body of mass m is fired straight from the surface of larger star towards smaller star. what should be its minimum speed to reach the surface of smaller star?

**Asked By: ASHISH**4 year ago

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Can two particles be in equilibrium under the action of their mutual gravitational force ? Can three particles

be ? Can one of the three particles be ?

**Asked By: ANMOL**4 year ago

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**If L is the angular momentum of a satellite revolving around earth is a circular orbit of radius r with speed v, then (i) L α v**

**(ii) L α r**

**(iii) L α √v**

**(iv) L α √r**

**Asked By: SWATI KAPOOR**5 year ago

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**Answer Strategies and trick by Manish sir**(it will help you to solve it by yourself)

L = m*v*r

**If potential energy of a body of mass m on the surface of earth is taken as zero then its potential energy at height h above the surface of earth is [ R is radius of earth and M is mass of earth]**

**Asked By: SWATI KAPOOR**5 year ago

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**Answer Strategies and trick by Manish sir**(it will help you to solve it by yourself)

[-GMm/(R+h)]-[-GMm/R] = GMm[1/R - 1/(R+h)]

solve ?

**Two points masses having m and 4m are placed at distance at r. The gravitational potential at a point, where gravitational field intensity zero is**

**Asked By: SWATI KAPOOR**5 year ago

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**Answer Strategies and trick by Manish sir**(it will help you to solve it by yourself)

field intensity at distance x from m = Gm/x^{2} - G4m/(r-x)^{2}

compare it to 0 and find x

then calculate gravitational potential at the point

**During motion of a planet from perihelion to aphelion the work done by gravitational force of sun on it is positive or negative.**

**Asked By: SWATI KAPOOR**5 year ago

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**Answer Strategies and trick by Manish sir**(it will help you to solve it by yourself)

change in K E = work done by all the forces

and **from perihelion to aphelion velocity decreases**

**so work done will be negative**

**If an object is projected vertically upwards with speed, half the escape speed of earth , then the maximum height attained by it is [R is radius of earth]**

**Asked By: SWATI KAPOOR**5 year ago

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**Answer Strategies and trick by Manish sir**(it will help you to solve it by yourself)

from ground to that point

1/2 m[√(2gR)/2]^{2 } + [-GMm/R] = 0 + [-GMm/(R+h)]

solve for h