Q. A mass 'm' is lifted to a height 'h' above the Earth's surface. What is the change in gravitational potential energy?
A.mgh
B.mg(h + R)
C.mgR
D.0
Solution
The change in gravitational potential energy when a mass m is lifted to a height h is given by ΔU = mgh.
Correct Answer: A — mgh
Q. A mass m is lifted to a height h in a uniform gravitational field. What is the work done against gravity?
A.mgh
B.gh
C.mg
D.0
Solution
The work done against gravity when lifting a mass m to a height h is given by W = mgh.
Correct Answer: A — mgh
Q. A satellite is in a circular orbit around the Earth. If it moves to a higher orbit, what happens to its potential energy?
A.It increases.
B.It decreases.
C.It remains constant.
D.It becomes zero.
Solution
As the satellite moves to a higher orbit, its gravitational potential energy increases due to the increase in distance from the Earth's center.
Correct Answer: A — It increases.
Q. A satellite is in a circular orbit around the Earth. If its speed is doubled, what will happen to its orbital radius?
A.It will remain the same.
B.It will double.
C.It will increase by a factor of four.
D.It will decrease by a factor of four.
Solution
If the speed of a satellite is doubled, the orbital radius will decrease by a factor of four, as orbital speed is inversely proportional to the square root of the radius.
Correct Answer: D — It will decrease by a factor of four.
Q. A satellite is in a circular orbit around the Earth. If its speed is increased, what will happen to its orbit?
A.It will remain circular
B.It will become elliptical
C.It will crash into the Earth
D.It will escape Earth's gravity
Solution
Increasing the speed of a satellite in a circular orbit will cause its orbit to become elliptical.
Correct Answer: B — It will become elliptical
Q. A satellite is in a circular orbit around the Earth. If the radius of the orbit is halved, what happens to the gravitational force acting on the satellite?
A.It remains the same
B.It doubles
C.It quadruples
D.It decreases by half
Solution
The gravitational force is inversely proportional to the square of the distance; halving the radius increases the force by a factor of four.
Correct Answer: C — It quadruples
Q. A satellite is in a circular orbit around the Earth. What happens to its gravitational potential energy as it moves to a higher orbit?
A.It increases.
B.It decreases.
C.It remains constant.
D.It becomes zero.
Solution
As the satellite moves to a higher orbit, its distance from the Earth increases, leading to an increase in gravitational potential energy.
Correct Answer: A — It increases.
Q. A satellite is in a circular orbit around the Earth. What is the gravitational potential energy of the satellite?
A.It is positive.
B.It is negative.
C.It is zero.
D.It is constant.
Solution
The gravitational potential energy of a satellite in orbit is negative due to the attractive force of gravity.
Correct Answer: B — It is negative.
Q. A satellite is in a circular orbit at a height of 300 km above the Earth's surface. What is the approximate speed of the satellite?
A.7.9 km/s
B.5.0 km/s
C.10.0 km/s
D.3.5 km/s
Solution
The orbital speed can be calculated using the formula v = √(GM/r). For a height of 300 km, the speed is approximately 7.9 km/s.
Correct Answer: A — 7.9 km/s
Q. A satellite is in a polar orbit. What is the significance of this orbit?
A.It allows the satellite to cover the entire surface of the Earth.
B.It is the fastest orbit available.
C.It is used only for communication satellites.
D.It is the most stable orbit.
Solution
A polar orbit allows the satellite to pass over the entire surface of the Earth as the planet rotates beneath it.
Correct Answer: A — It allows the satellite to cover the entire surface of the Earth.
Q. At what point between two equal masses does the gravitational force become zero?
A.At the midpoint
B.At a point closer to one mass
C.At a point closer to the other mass
D.It never becomes zero
Solution
The gravitational forces exerted by both masses cancel each other out at the midpoint.
Correct Answer: A — At the midpoint
Q. At what point in a gravitational field is the gravitational potential constant?
A.At the center of the mass
B.At infinity
C.Along an equipotential surface
D.At the surface of the mass
Solution
The gravitational potential is constant along an equipotential surface.
Correct Answer: C — Along an equipotential surface
Q. At what point in space is the gravitational potential zero?
A.At the center of the Earth.
B.At infinity.
C.At the surface of the Earth.
D.At the center of the Moon.
Solution
The gravitational potential is considered zero at infinity.
Correct Answer: B — At infinity.
Q. How does the gravitational field strength vary with distance from a point mass?
A.It increases linearly.
B.It decreases with the square of the distance.
C.It remains constant.
D.It decreases linearly.
Solution
The gravitational field strength decreases with the square of the distance from the point mass.
Correct Answer: B — It decreases with the square of the distance.
Q. How does the gravitational potential change as you move away from a planet?
A.It increases.
B.It decreases.
C.It remains constant.
D.It oscillates.
Solution
The gravitational potential decreases as you move away from a planet.
Correct Answer: B — It decreases.
Q. How does the gravitational potential energy of a system of two masses change as they move closer together?
A.It increases.
B.It decreases.
C.It remains constant.
D.It becomes zero.
Solution
The gravitational potential energy decreases as the two masses move closer together.
Correct Answer: B — It decreases.
Q. How does the gravitational potential energy of an object change when it is lifted to a height 'h' above the ground?
A.It decreases.
B.It increases.
C.It remains the same.
D.It becomes zero.
Solution
The gravitational potential energy increases as the object is lifted to a height 'h' above the ground.
Correct Answer: B — It increases.
Q. If a satellite is moved to a higher orbit, what happens to its orbital period?
A.It decreases.
B.It increases.
C.It remains the same.
D.It becomes zero.
Solution
The orbital period of a satellite increases when it is moved to a higher orbit, according to Kepler's third law.
Correct Answer: B — It increases.
Q. If a satellite is moving in a circular orbit, what type of energy does it possess?
A.Only kinetic energy
B.Only potential energy
C.Both kinetic and potential energy
D.Neither kinetic nor potential energy
Solution
A satellite in a circular orbit possesses both kinetic energy due to its motion and potential energy due to its position in the gravitational field.
Correct Answer: C — Both kinetic and potential energy
Q. If a satellite's altitude is increased, what happens to its orbital period?
A.It decreases
B.It increases
C.It remains constant
D.It becomes zero
Solution
As the altitude increases, the orbital period increases due to the greater distance from the Earth's center.
Correct Answer: B — It increases
Q. If a satellite's speed is less than the required orbital speed, what will happen?
A.It will remain in orbit.
B.It will fall back to Earth.
C.It will escape into space.
D.It will move to a higher orbit.
Solution
If a satellite's speed is less than the required orbital speed, it will not have enough centripetal force to maintain its orbit and will fall back to Earth.
Correct Answer: B — It will fall back to Earth.
Q. If an object is moved to a height equal to the radius of the Earth, how does the gravitational force acting on it change?
A.It becomes half
B.It becomes one-fourth
C.It remains the same
D.It becomes zero
Solution
At a height equal to the radius of the Earth, the gravitational force becomes one-fourth of its value at the surface.
Correct Answer: B — It becomes one-fourth
Q. If the distance between two masses is doubled, how does the gravitational force change?
A.It becomes four times weaker
B.It becomes twice weaker
C.It remains the same
D.It becomes four times stronger
Solution
According to the inverse square law, if the distance is doubled, the force becomes 1/(2^2) = 1/4, or four times weaker.
Correct Answer: A — It becomes four times weaker
Q. If the distance between two masses is doubled, how does the gravitational force between them change?
A.It becomes four times weaker
B.It becomes twice as strong
C.It remains the same
D.It becomes half as strong
Solution
According to the inverse square law, if the distance is doubled, the force becomes 1/(2^2) = 1/4 of the original force.
Correct Answer: A — It becomes four times weaker
Q. If the distance between two masses is halved, how does the gravitational force change?
A.It becomes four times stronger
B.It becomes twice stronger
C.It remains the same
D.It becomes half as strong
Solution
If the distance is halved, the force becomes 1/(1/2)^2 = 4 times stronger.
Correct Answer: A — It becomes four times stronger
Q. If the distance from a mass is doubled, how does the gravitational field strength change?
A.It doubles.
B.It halves.
C.It becomes one-fourth.
D.It becomes one-eighth.
Solution
The gravitational field strength is inversely proportional to the square of the distance, so it becomes one-fourth.
Correct Answer: C — It becomes one-fourth.
Q. If the distance from the center of the Earth is doubled, how does the gravitational potential change?
A.It doubles.
B.It halves.
C.It becomes zero.
D.It quadruples.
Solution
The gravitational potential is inversely proportional to the distance, so if the distance is doubled, the potential halves.
Correct Answer: B — It halves.
Q. If the distance from the center of the Earth is doubled, how does the gravitational field strength change?
A.It doubles.
B.It halves.
C.It becomes zero.
D.It quadruples.
Solution
The gravitational field strength varies inversely with the square of the distance, so if the distance is doubled, the field strength becomes 1/4.
Correct Answer: B — It halves.
Q. If the distance from the center of the Earth is doubled, what happens to the gravitational field strength?
A.It doubles.
B.It halves.
C.It becomes one-fourth.
D.It becomes zero.
Solution
The gravitational field strength varies inversely with the square of the distance from the center of the Earth, so if the distance is doubled, the field strength becomes one-fourth.
Correct Answer: C — It becomes one-fourth.
Q. If the Earth were to suddenly shrink in size but maintain its mass, what would happen to the gravitational force at its surface?
A.It would increase
B.It would decrease
C.It would remain the same
D.It would become zero
Solution
If the Earth shrinks in size while maintaining its mass, the gravitational force at the surface would increase due to the decrease in radius.
