Q.1.
The gravitational potential energy of a rocket of mass 100kg at a distance 109 m from earth surface is 4 × 107 joule. The weight of the rocket in Newton's at distance 109 m from earth is ( Re=6400 km)
-
14%
a) 8 ×10-2 N
-
14%
b) 8 × 10-3 N
-
57%
c)4 × 10-3 N
-
14%
d)4 × 10-2N
Explanation
Q.2.
A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is [ MNR 1986]
-
0%
a) positive
-
40%
b) negative
-
40%
c) zero
-
20%
d) may be positive or negative depending upon its initial velocity
Q.3.
Consider a satellite going round the earth in a circular orbit. Which of the following statements is wrong?
-
40%
a)It is freely falling body
-
60%
b) It is acted upon by a force directed away from the center of the earth which counter-balances the gravitational pull
-
0%
c)It is moving with constant speed
-
0%
d)Its angular momentum remains constant
Q.4.
Imagine a light planet revolving around a very massive star in circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between planet and star is proportional t R-5/2, then T2 is proportional to ..[ IIT 1989]
-
0%
a) R3
-
20%
b) R7/2
-
80%
c)R5/2
-
0%
d)R3/2
Explanation
Q.5.
A spherical planet far out in space has a mass Mo and diameter Do. A particle of mass m falling freely near the surface of this planet will experience acceleration due to gravity which is equal to [ MPPMT 1987]
-
50%
a) GMo / D20
-
25%
b) 4m GMo / D20
-
25%
c) 4GMo / D20
-
0%
d) GmMo / D20
Q.6.
Which of the following represents the Newton's law of universal gravitation correctly
-
60%
a)
-
0%
b)
-
40%
c)
-
0%
d)
Q.7.
The gravitational potential at any point distant r from a point mass m is work done in moving a unit mass from
-
0%
a)the point of interest to infinity
-
33%
b) from infinity to the point of interest
-
67%
c)from the position of point mass m to the point of interest
-
0%
d)from infinity to the position of point mass m
Q.8.
If earth ware to cease rotating about its own axis, the increase in the value of g is C.G.S system at equator is nearly
-
57%
a) 3.36 cm/s2
-
0%
b) 6.72 cm/s2
-
29%
c)1.68 cm/s2
-
14%
d)0.84 cm/s2
Q.9.
An astronaut orbiting the earth in a circular orbit 120km above the surface of earth, gently drops a spoon from the spaceship. The spoon will [Raj-PMT 1996]
-
25%
a) fall vertically down to the earth
-
50%
b) move towards the moon
-
25%
c)will move along with the spaceship
-
0%
d)will move in an irregular way and then fall down to earth
Q.10.
The earth revolves round the sun in an elliptical orbit. Its speed is
-
20%
a) goes on decreasing continuously
-
40%
b) greatest when it is closest to the sun
-
0%
c) greatest when it is farthest from the sun
-
40%
d) constant at all the points on the orbit
Q.11.
Two satellites A and B go around a planet P in circular orbit having radii 4R and R respectively if the speed of the satellite a is 3V, the speed of the satellite B will be [ MNR 1991]
-
0%
a)12V
-
25%
b) 6V
-
75%
c)(4/3)V
-
0%
d)(3/2)V
Q.12.
In a gravitational field, at a point where the gravitational potential is zero
-
60%
a) the gravitational field is necessarily zero
-
0%
b) the gravitational field is not necessarily zero
-
40%
c)nothing can be said definitely about gravitational field
-
0%
d)none of the above
Q.13.
A satellite is orbiting around the earth in the equatorial plane rotating from west to east as the earth does. If ωe is angular velocity of earth and ωs is angular velocity of satellite, then the satellite will appear at the same location after a time t=
-
40%
a)
-
60%
b)
-
0%
c)
-
0%
d)
Q.14.
A solid sphere of uniform density and mass M has a radius of 4m. Its center is at the origin of coordinate system. Two sphere of radii 1 m are taken out so that their centers are at P(0, -2, 0) and Q(0, 2, 0) respectively. This leaves two spherical cavities. What is the gravitational field at the center of each cavity
-
25%
a) (31/1024) GM
-
50%
b) GM/ 1024
-
0%
c) 31 GM
-
25%
d) GM
Explanation
Q.15.
The tail of the Comet Halley is directed away from sun due to the fact that..[ CPMT 1988]
-
25%
a)As the comet rotates around the sub the lighter mass of the comet is pushed away due to centrifugal force only
-
25%
b) as the comet rotates, the lighter mass of the comet is attracted by some star situated in direction of the tail
-
50%
c)the radiation emitted by the sun exerts a radiant pressure on the comet throwing its tail away from sun
-
0%
d)the tail of the comet always exists in the same orientation
Q.16.
Kepler's second law states that the straight line joining the planet to the sun sweeps out equal areas in equal times. This statement is equivalent to saying that
-
20%
a) total acceleration is zero
-
20%
b) transverse acceleration is zero
-
60%
c)tangential acceleration is zero
-
0%
d)radial acceleration is zero
Q.17.
Suppose the gravitational force varies inversely as the nth power of the distance. Then the time period of the planet in circular orbit of radius R around the sun will b proportional to
-
0%
a) R-n
-
0%
b) Rn
-
50%
c) R(n-1)/2
-
50%
d) R(n+1)/2
Explanation
Q.18.
The point masses m1 and m2 are initially at rest and at infinite distance apart. They start moving towards one another under their mutual gravitation field. There relative speed when they are at distance d apart is ;
-
25%
a)
-
50%
b)
-
25%
c)
-
0%
d)
Explanation
Q.19.
A planet moves around the sun. At a point P it is closest from the sun at a distance d1 and has a speed vAt another point Q, when it is farthest fron the sun at a distance d2, its speed will be [ MPPMT 1987]
-
33%
a) d12v1 / d22
-
67%
b) d2v1 / d1
-
0%
c) d1v1 / d2
-
0%
d) d22v1 / d12
Q.20.
A body weight with a spring balance in a train at rest, shows a weight WWhen the train begins to move with a velocity v around the equator from west to east and if the angular velocity of earth is ω
-
0%
a)W0
-
33%
b) W0 ( 1 + 2vω/g)
-
67%
c)W0( 1 - 2vω/g)
-
0%
d)W0( 1 - v2 / R)
Explanation
Q.21.
A hydrogen balloon released on the moon would
-
0%
a) climb with an acceleration of 9.8×6 m/s2
-
33%
b) climb with an acceleration of 9.8 / 6 m/s2
-
0%
c)neither climb nor fall
-
67%
d)fall with an acceleration of 9.8 / 6 m/s2
Q.22.
A body is dropped from a communication satellite around the earth. Which of the following statements is not correct?
-
0%
a)the body is falling continuously towards the center of earth
-
33%
b) the body will hit the surface of the earth
-
33%
c)the body will move into circular orbit around the earth
-
33%
d)the body will appear to be stationary when observed from the earth
Q.23.
A satellite in force-free space sweeps stationary interplanetary dust at rate dM/dt=αv, where M is the mass and v is the velocity of the satellite and α is constant. What is the deceleration of the satellite: [ CBSE 1994]
-
0%
a) -2αv2 / M
-
67%
b) - αv2 / M
-
33%
c) - αv2 / 2M
-
0%
d) - αv2
Q.24.
Acceleration due to gravity, g and the mean density of the earth ρ are related by the relation [ BHU 1998]
-
0%
a)
-
67%
b)
-
33%
c)
-
0%
d)
Explanation
Q.25.
Choose the correct statement from the following:The radius of the orbit of a geostationary satellite depends upon [ PMT 1995]
-
33%
a) mass of the satellite, its time period and gravitational constant
-
33%
b) mass of the satellite, mass of the earth and the gravitational constant
-
0%
c)mass of the earth, mass of the satellite, time period of the satellite and the gravitational constant
-
33%
d)mass of the earth, time period of the satellite and the gravitational constant
Explanation
Q.26.
The gravitational field due to a mass distribution is E=K/x3 in the direction. ( K is a constant). Taking the gravitational potential to be zero at infinity, its value at a distance x is ..[ MPPMT 1994]
-
33%
a) K/x
-
33%
b) K/2x
-
33%
c)K/x2
-
0%
d)K/2x2
Q.27.
To purchase a sugar will be beneficial at [ Raj PET 1996]
-
67%
a) Poles
-
0%
b) Equator
-
0%
c) At 45° altitudes
-
33%
d) At altitude 40°
Q.28.
A satellite moves east wards with a speed V0 in equatorial plane, very near to the surface of earth. Another satellite moves West wards in the same orbit with same speed. if R=radius of earth and ω, the angular speed of earth about its own axis, then the difference in time periods of satellites as observed from earth is
-
100%
a)
-
0%
b)
-
0%
c)
-
0%
d)
Explanation
Q.29.
At what height over the earth's pole, the free fall acceleration decreases by one percent? ( Assume the radius of earth to be 6400 km) [ CET 1994]
-
33%
a) 32 km
-
33%
b) 64 km
-
0%
c)80 km
-
33%
d)1.253 km
Q.30.
the diameters of two planets are in the ratio 4:1 and their mean densities in the ratio 1:The acceleration due to gravity on the planets will be in ratio....[ ISM Dhanbad 1994]
-
0%
a) 1:2
-
67%
b) 2:3
-
0%
c)2:1
-
33%
d)4:1
Explanation
