# Newtonâ€™s Law of Gravitation Problems

### Gravitation Practice Paper:

Ques. Hubble’s law states that the velocity with which milky way is moving away from the earth is proportional to
(a) Square of the distance of the milky way from the Earth
(b) Distance of milky way from the Earth
(c) Mass of the milky way
(d) Product of the mass of the milky way and its distance from the Earth

Ans. (b)

Ques. 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 present day length reduced by
(a) 1/4
(b) 1/2
(c) 1/8
(d) 1/6

Ans. (c)

Ques. A body is projected vertically upwards from the surface of a planet of radius R with a velocity equal to half the escape velocity for that planet. The maximum height attained by the body is
(a) R/3
(b) R/2
(c) R/4
(d) R/5

Ans. (a)

Ques. A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of earth
(a) The acceleration of S is always directed towards the centre of the earth
(b) The angular momentum of S about the centre of the earth changes in direction but its magnitude remains constant
(c) The total mechanical energy of S varies periodically with time
(d) The linear momentum of S remains constant in magnitude

Ans. (a)

Related: Set theory problems

Ques. 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)
(a) 32 km
(b) 80 km
(c) 1.253 km
(d) 64 km

Ans. (a)

Ques. A mass M is split into two parts, m and (Mâ€“m), which are then separated by a certain distance. What ratio of m/M maximizes the gravitational force between the two parts
(a) 1/3
(b) 1/2
(c) 1/4
(d) 1/5

Ans. (b)

Ques. Weightlessness experienced while orbiting the earth in space-ship, is the result of
(a) Inertia
(b) Acceleration
(c) Zero gravity
(d) Free fall towards Earth

Ans. (d)

Ques. If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth’s surface would
(a) Decrease by 2%
(b) Remain unchanged
(c) Increase by 2%
(d) Increase by 1%

Ans. (c)

Ques. Gravitational mass is proportional to gravitational
(a) Field
(b) Force
(c) Intensity
(d) All of these

Ans. (d)

Ques. The radius and mass of earth are increased by 0.5%. Which of the following statements are true at the surface of the Earth
(a) g will increase
(b) g will decrease
(c) Escape velocity will remain unchanged
(d) Potential energy will remain unchanged

Ans. (b, c, d)

Ques. If there were a smaller gravitational effect, which of the following forces do you think would alter in some respect
(a) Viscous forces
(b) Archimedes uplift
(c) Electrostatic force
(d) None of these

Ans. (b)

Ques. A body of mass m is taken from earth surface to the height h equal to radius of earth, the increase in potential energy will be
(a) mgR
(b) Â½ mgR
(c) 2 mgR
(d) Â¼ mgR

Ans. (b)

Ques. A spring balance is graduated on sea level. If a body is weighed with this balance at consecutively increasing heights from earth’s surface, the weight indicated by the balance
(a) Will go on increasing continuously
(b) Will go on decreasing continuously
(c) Will remain same
(d) Will first increase and then decrease

Ans. (b)

Ques. A satellite is launched into a circular orbit of radius R around the earth. A second satellite is launched into an orbit of radius (1.01)R. The period of the second satellite is larger than that of the first one by approximately
(a) 0.5%
(b) 1.0%
(c) 1.5%
(d) 3.0%

Ans. (c)

Ques. If the earth stops rotating, the value of â€˜gâ€™ at the equator will
(a) Increase
(b) Remain same
(c) Decrease
(d) None of these

Ans. (a)

Ques. If the distance between the earth and the sun becomes half its present value, the number of days in a year would have been
(a) 64.5
(b) 129
(c) 182.5
(d) 730

Ans. (b)

Ques. A rocket is launched with velocity 10 km/s. If radius of earth is R, then maximum height attained by it will be
(a) 2R
(b) 3R
(c) 4R
(d) 5R

Ans. (c)

Ques. A geostationary satellite orbits around the earth in a circular orbit of radius 36000 km. Then, the time period of a satellite orbiting a few hundred kilometres above the earthâ€™s surface (REarth = 6400 km) will approximately be
(a) 1/2 h
(b) 1 h
(c) 2 h
(d) 4 h

Ans. (c)

Ques. At what height from the ground will the value of â€˜gâ€™ be the same as that in 10 km deep mine below the surface of earth
(a) 20 km
(b) 10 km
(c) 15 km
(d) 5 km

Ans. (a)

Ques. Mass M is divided into two parts xM and (1 â€“ x)M. For a given separation, the value of x for which the gravitational attraction between the two pieces becomes maximum is
(a) 1/2
(b) 3/5
(c) 1
(d) 2

Ans. (a)

Ques. The tidal waves in the sea are primarily due to
(a) The gravitational effect of the moon on the earth
(b) The gravitational effect of the sun on the earth
(c) The gravitational effect of venus on the earth
(d) The atmospheric effect of the earth itself

Ans. (a)

Ques. The weight of a body at the centre of the earth is
(a) Infinite
(b) Same as on the surface of earth
(c) None of these
(d) Zero

Ans. (d)

Ques. The atmosphere is held to the earth by
(a) Winds
(b) Gravity
(c) Clouds
(d) None of these

Ans. (b)

Ques. Who among the following gave first the experimental value of G?
(a) Copernicus
(b) None of these
(c) Cavendish
(d) Brook Teylor

Ans. (c)

Related: Biomolecules Quizlet

Ques. The force of gravitation is
(a) Repulsive
(b) Electrostatic
(c) Conservative
(d) Non-conservative

Ans. (c)

Ques. If a force â€˜fâ€™ action on a mass â€˜mâ€™ produces acceleration â€˜aâ€™ then as per Newtonâ€™s second law of motion :
(a) f = ma
(b) f = a/m
(c) f = m/a
(d) m = af

Ans. (a)