A body is projected vertically from the surface of the earth of radius R with velocity equal to half of the escape velocity. The maximum height reached by the body is
  • R
  • R/2
  • R/3
  • R/4
The radius of the earth is 6400 km and g = 10 m/s². In order that a body of 5 kg weighs zero at the equator, the angular speed of the earth is
  • 1/80 rad /s
  • 1/400 rad /s
  • 1/800 rad /s
  • 1/1600 rad /s
A body weighs 500 N on the surface of the earth. How much would it weight half way below the surface of the earth?
  • 1000 N
  • 500 N
  • 250 N
  • 125 N
The time - period of a satellite of earth is 5 hours. If the separation between the earth and the satellite is increased to 4 times the previous value, the new time - period will become
  • 10 hours
  • 20 hours
  • 40 hours
  • 80 hours
A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is
  • Positive
  • Negative
  • Zero
  • may be positive or negative
What would be the duration of the year if the distance between the earth and the sun gets doubled?
  • 1032 days
  • 129 days
  • 365 days
  • 730 days
If a body of mass m is taken out from a point below the surface of earth equal to half the radius of earth, R, to a height R above the earths surface, then work done on it will be
  • (5/6) mgR
  • (6/7) mgR
  • (7/8) mgR
  • (8/9) mgR
A artificial satellite moving in a circular orbit around the earth has a total (kinetic + potential) energy EIts potential energy is
  • 2E0
  • E0
  • 1.5 E0
  • -E0
The escape velocity for a body projected vertically upwards from the surface of the earth is 11 km/s. If the body is projected at an angle of 450 with the vertical, the escape velocity will be
  • 11/√2 km/s
  • 11√2 km/s
  • 2 km/s
  • 11 km/s
There is no atmosphere on the moon because
  • it is closer to the earth
  • it revolves round the earth
  • it gets light from the sun
  • the escape velocity of gas molecules is less than their root mean square velocity here
The value of g at a particular point is 9.8 m/sec² suppose the earth suddenly shrink uniformly to half its present size without losing any mass. The value of g at the same point (assuming that the distance of the point from the centre of the earth does not shrink) will become
  • 9.8 m/sec²
  • 4.9 m/sec²
  • 19.6 m/sec²
  • 2.45 m/sec²
If the radius of the earth were to be raise by 1% its mass remaining the same, the acceleration due to gravity on the surface of the earth will
  • increase by 1%
  • decrease by 2%
  • decrease by 1%
  • increase by 2%
The escape velocity of projection from the earth is approximately (R = 6400 km)
  • 7 km/sec
  • 112 km/sec
  • 12.2 km/sec
  • 1.1 km/sec
Who among the following first gave the experimental velocity of G?
  • Cavendish
  • Copernicus
  • Brook Taylor
  • none of these
A satellite S is move in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth .
  • The acceleration of S is always directed towards the centre of the earth.
  • The angular momentum of S about the centre of the earth changes in direction, but its magnitude remains constant.
  • The total mechanical energy of S varies periodically with time.
  • The linear momentum of S remains constant in magnitude.
The mean radius of the earth is R, its angular speed on its own axis is w and the acceleration due to gravity at earths surface is g. The cube of the radius of the orbit of a geo-stationary satellite will be
  • r²g / w
  • R²w²/ g
  • RG w²
  • R²g / w²
If the distance between the earth and the sun were half its present value, the number of day in a year would have been
  • 64.5
  • 129
  • 182.5
  • 730
The masses of two planets are in the ratio 1 :Their radii are in the ratio 1 :The acceleration due to gravity on the planets are in the ratio.
  • 1 : 2
  • 2 : 1
  • 3 : 5
  • 5 : 3
0 h : 0 m : 1 s

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