# Practice Test

Q1) Newton's law of gravitation is applicable for: Show Answer

Q2) Which of the following interactions is the weakest? Show Answer

Q3) The weight of the body at the centre of earth is: Show Answer

Q4) To what height the body is to be raised so that force of gravity on it is 1% of the value on the surface of earth? (Radius of earth is 6400 km) Show Answer

Q5) The tidal waves in the sea are primarily due to the: Show Answer

Q6) A body of mass 'm' taken from earth surface to a height equal to the radius of earth, the changes in its potential energy is (letters have usual meaning): Show Answer

Q7) The weight of the body at earth's surface is W. At a depth half way to the centre of earth its weight will be (Density uniform): Show Answer

Q8) If radius of earth shrinks by 2% (mass remaining same), how much will be the change in value of 'g' ? Show Answer

Q9) Minimum work done to shift a body of mass 'm' from a circular orbit of 2R to a higher orbit of radius 3R around the earth (R = Radius of earth): Show Answer

Q10) A satellite is moving around the earth at a height of 10 km from the surface of earth. The weight of man who weighs 60 kg on earth is: Show Answer

Q11) The escape velocity of a body from earth is 11 km/sec. What will be its value from a planet whose radius is double but density is same as that of earth? Show Answer

Q12) The time period of simple pendulum in a satellite is: Show Answer

Q13) A package is released from a satellite by simply detaching it from the outer wall of the satellite. What will happen to the package? Show Answer

Q14) A satellite is rotating close to earth. In order to make it escape the gravitational field, its velocity is to be increased by: Show Answer

Q15) Ratio of K.E. required for the satellite to escape the earth's surface to the K.E. required to orbit just close to the earth is: Show Answer

Q16) A satellite is in circular orbit 140 km above the planet. If the radius of planet is 5760 km then gravitational force on satellite compared with that when it is at the planet's surface is approximately is: Show Answer

Q17) Kepler's second law regarding constancy of aerial velocity of a planet is a consequence of the law of conservation of: Show Answer

Q18) The acceleration due to gravity on the moon is 1/6th that on the earth. If their densities are the same, the radius of moon is: (R' is the radius of earth) Show Answer

Q19) The atmosphere is held to earth by: Show Answer

Q20) Moon has no atmosphere because: Show Answer

Q21) A satellite is revolving around the earth in a circular orbit 4 times the radius of the parking orbit. The time period of the satellite is: Show Answer

Q22) If earth were a hallow sphere, what will be the intensity of gravitational field inside it? Show Answer

Q23) A satellite revolving close to earth has a K.E., E. What energy should be given to it so as to make it escape the gravitational pull to earth? Show Answer

Q24) If the radius of earth is reduced by 1% keeping the mass unchanged, the change in acceleration due to gravity is: Show Answer

Q25) Infinite number of masses each of 3.0 kg are placed along x-axis at distance 1 m, 2 m, 4 m, 8 m from origin O on the axis, if G is the gravitational constant. The magnitude of gravitational field is: Show Answer

Q26) Infinite number of masses each of 2 kg are placed along x-axis at distance 1 m, 2 m, 4 m, 8 m from the origin O, what is the magnitude of gravitational potential at 'O'? (G = gravitational constant): Show Answer

Q27) A satellite is moving in an orbit with half the speed required to escape the earth's field. What is the height of the satellite? Show Answer

Q28) With what speed the earth should rotate about its own axis so that a person should weigh at the equator 3/5th of his weight at present? (Take R = 6400 km) Show Answer

Q29) A body is orbiting around the earth at a mean radius 4 times as great as the parking orbit of a satellite. The period of revolution of the body is: Show Answer

Q30) If the satellite is stopped suddenly in its orbit and is allowed to fall freely into the earth's surface with what speed it hits the surface of earth? Show Answer

Q31) A missile is launched with a velocity less than the escape velocity. The sum of its K.E. and P.E. is : Show Answer

Q32) The length of the day when earth rotates fast enough to reduce the weight of the body at the equator to be zero: Show Answer

Q33) The eccentricity of earth's elliptical orbit is 0.0167. The ratio of maximum speed to minimum speed in the orbit is:

Q34) The closest planet to the earth is: Show Answer

Q35) The K.E. needed to move the body to infinite distance is: Show Answer

Q36) A reel of massless thread unrolls itself falling down under gravity. The acceleration of its fall is: Show Answer

Q37) The force of gravity is the least at: Show Answer

Q38) The weight of a body at a height equal to the radius of the earth is W, its weight at a height equal to three times the radius of the earth will be: Show Answer

Q39) You are given 32 balls identical in weight and shape except one which is heavier in weight than others. If a scale beam is provided but no weight box is available how many minimum number of weightings have to be made so as to isolate the heavier ball? Show Answer

Q40) A star shrinks suddenly and its density increases 10 times its original value. The acceleration due to gravity increases by a factor of: Show Answer

Q41) Three identical objects each of mass M move along circle of radius R under the action of their mutual gravitational attraction, the speed of each is: Show Answer

Q42) Period of revolution of planet A is 8 times that of B. The distance of A from sun is how many times greater than that of B from the sun? Show Answer

Q43) The escape velocity from earth is 11.2 km/s if the earth's mass increases to twice and radius is reduced to half of the present values. What will be escape velocity? Show Answer

Q44) The weight of a man in a lift moving upwards is 608 N while the weight of the same man in the lift moving downwards with the same acceleration is 368 N. His normal weight in newton is: Show Answer

Q45) 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: Show Answer

Q46) Two spherical bodies of mass M and 5M and radii R and 2R respectively are released in free space with initial separation between their centers equal to 12R. If they attract each other due to gravitational force only then the distance covered by the smaller body just before collision is: Show Answer

Q47) Average density of the earth: Show Answer

Q48) A particle of mass 10 g is kept in the surface of uniform sphere of mass 100kg and radius 10 cm. Find the work done against the gravitational force between them to take the particle far away from the sphere. Show Answer

Q49) The escape velocity on the surface of the earth is 11.2 km/s. What would be the escape velocity on the surface of another planet of the same mass but 1/4 times the radius of the earth? Show Answer

Q50) A body weighs 72 N on the surface of earth. What is the gravitational force on it due to earth at a height equal to half the radius of the earth from the surface? Show Answer

Q51) Knowing that mass of moon is M/81, where M is the mass of earth, find the distance of the point from the moon, where gravitational field due to earth and moon cancel each other. Given that distance between earth and moon is 60 R, where R is the radius of earth. Show Answer

Q52) A satellite is in an orbit around the earth. If its kinetic energy is doubled, then: Show Answer

Q53) Ratio of inertial mass to gravitational mass is: Show Answer

Q54) The mass of the earth is 81 times that of the moon and the radius of the earth is 3.5 times that of the moon. The ratio of the escape velocity on the surface of earth to that on the surface of moon will be: Show Answer

Q55) If mass of body is M on the earth's surface, then the mass of the same body on the moon's surface is: Show Answer

Q56) If the radius of earth's orbit is made 1/4, the duration of an year will become: Show Answer

Q57) The distance of geostationary satellite from centre of earth is nearest to: Show Answer

Q58) A satellite is placed in a circular orbit around earth at such a height that it always remains stationary with respect to earth's surface. In such case, its height from the earth's surface is: Show Answer

Q59) Escape velocity on the earth: Show Answer

Q60) The colour of star indicates its: Show Answer

Q61) The time period of planet X around sun is 8 times that of Y. The distance of X from the sun is how many times greater than that of Y? Show Answer

Q62) Feeling of weightlessness in a satellite or spaceship is due to Show Answer

Q63) If the spinning speed of the earth is increased, then the weight of the body at equator: Show Answer

Q64) Mass of the earth has been determined through: Show Answer

Q65) The force of gravitation is : Show Answer

Q66) The period of revolution of a certain planet in an orbit of radius R is T. Its period of revolution is an orbit of radius 4 R will be: Show Answer

Q67) When radius of earth is reduced by 1% without changing the mass then change in acceleration due to gravity will be: Show Answer

Q68) The mass of a body of the moon is less than on earth. The gravitational force is less in moon than on the earth. Of the two statements: Show Answer

Q69) The duration of day is highest at: Show Answer

Q70) The acceleration due to gravity in the planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2m on the surface of A. What is the height of jump by the same person on the planet B? Show Answer

Q71) The velocity with which a projectile must be fired so that it escapes earth's gravitation, does not depend on: Show Answer

Q72) A satellite orbiting around earth of radius R is shifted to an orbit of radius 2R. How many times the time taken for one revolution increase?

Q73) A satellite with kinetic energy E is revolving round the earth in a circular orbit. The minimum additional kinetic energy required for it to escape into outer space is: Show Answer

Q74) The difference in length of a mean solar day and a sidereal day is about: Show Answer

Q75) The density of newly discovered planet is twice that of earth. The acceleration due to gravity at the surface of the planet is equal to that at the surface of the earth. If the radius of the earth is R, the radius of the planet would be: Show Answer

Q76) In an orbital motion, the angular momentum vector is: Show Answer

Q77) The minimum kinetic energy needed to project a body form the earth's surface to infinity is: Show Answer

Q78) For a satellite moving in an orbit around the earth, the ratio of kinetic energy to potential energy is: Show Answer

Q79) The length of second pendulum is 1 m on earth. If mass and diameter of the planet is doubled than that of earth, then length becomes Show Answer

Q80) What effect occurs on the frequency of a pendulum if it is taken from the earth's surface to deep into a mine? Show Answer

Q81) Earth is revolving around the sun. If the distance of the earth from the sun is reduced to 1/4th of the present distance then the day length reduced to: Show Answer

Q82) A simple pendulum is taken from the equator to the pole. Its period: Show Answer

Q83) The period of a satellite in a circular orbit of radius R is T, the period of another satellite in a circular orbit of radius 4R is: Show Answer

Q84) Force of gravity is least at: Show Answer

Q85) The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If the speed of satellite A is 3 V, then the speed of satellite B will be: Show Answer

Q86) A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest: Show Answer

Q87) If the distance between the earth and the sun were half of its present value, the number of days in a year would have been: Show Answer

Q88) The escape velocity from earth is 11.2 km/sec. If the mass of the earth is doubled and radius is halved. The changed escape speed is: Show Answer

Q89) With what velocity should a particle be projected so that its height becomes equal to the radius of earth? Show Answer

Q90) Acceleration due to gravity on a planet 'A' is 9 times that at a planet B. A man jumps to height of 2 m on the surface of A. To what height he can jump on B? Show Answer

Q91) Two spheres of mass M and 5 M and radii R and 2 R are released in free space with initial distance between their centres being 12 R. If they move under gravitational force of attraction then the distance moved by smaller sphere just before collission is: Show Answer

Q92) A man weighs 60 kg at the surface of earth. At what height above the surface the weight becomes 30 kg? [given R = 6400 km] Show Answer

Q93) The variation of the acceleration due to gravity as one moves away from earth's centre is given by : Show Answer