Download Gravitational Topical Questions from 2021-2023 and more Study notes Physics in PDF only on Docsity!
Gravitational topical questions from 2021-
Question 1 : Jan 2021
A small satellite of mass 245 kg is orbiting the Earth. The radius of the orbit is equal to twice the radius of the Earth. The weight of the satellite in its orbit is about A zero. B 600N. C 1200N. D 2400N.
Question 2 : Jan 2021
The Earth is 9.3 times more massive than Mars. The gravitational field strength at the surface of the Earth is 2.6 times greater than at the surface of Mars. Calculate the mean radius of Mars. Mean radius of Earth = 6.37 ́10^6m (2) ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………….......................................... ....................................................................................................................................
Question 3: Jan 2021
Salyut 1 was the first Earth-orbiting space station. The Soviet Union built it and Launched into a low Earth orbit fifty years ago. (a) Salyut 1 orbited at an average height above the surface of the Earth of 211km. mass of Salyut 1 = 18 400kg mass of Earth = 5.98 x1024 kg radius of Earth =6. x10^6ḿ (i) A textbook claims that for astronauts in Salyut 1, there would be a sunrise 16 times every day.
Assess the validity of this claim. 1 day = 8.64 x10^4s (4) ́ ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………. (ii) Salyut 1 made almost three thousand orbits before falling back to Earth. Calculate the change in gravitational potential energy of Salyut1 as it fell back to Earth. (3) ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………. (iii) (b) Salyut 1 burned up over the Pacific Ocean as it re-entered the Earth’s atmosphere. Explain why Salyut1 burned up. (2) ……………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………
Question 4 : Jun 2021
The gravitational field strength on the surface of Mercury is gm. Calisto, a moon of Jupiter, has the same radius as Mercury but only one-third of its density. What is the gravitational field strength on the surface of Calisto? A gM/ B gM/ C 3gM D 9gM
Question 5 : Jun 2021
The gravitational field strength at the surface of the Moon is one sixth of that at the surface of the Earth. A simple pendulum has a period T at the surface of the Earth. What would be the time period of the same pendulum at the surface of the Moon?
A T/
BT/6^1/
C T
D Tx6^1/
Question 7 : Oct 2021
Sirius is the brightest star in the night sky. The intensity of Sirius is measured to be 1.09 × 10−7Wm−2. Calculate the distance of Sirius from the Earth. luminosity of Sirius = 8.94 × 1027W (2) …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………….
Question 8 : Oct 2021
Weather satellites may be in an equatorial orbit or a polar orbit, as shown.
(a) A weather satellite in a polar orbit circles the Earth at a height of 8.50 × 105m above the surface of the Earth. mass of Earth = 5.98 × 1024 kgradius of Earth = 6360km (i) Show that the gravitational potential at this height is about −5.5 × 107 Jkg−1. (2 ) (ii) Hence calculate the increase in gravitational potential energy when the satellite is placed in orbit. (2) satellite mass = 4990 kg gravitational potential at the Earth’s surface = −6.27 × 10^7 Jkg− ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………… (b) It is claimed that a satellite in orbit at a height of 8.50 × 105m would make 15 orbits of the Earth every 24 hours. Assess the validity of this claim.(5) ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… (c ) (c) It is suggested that the satellite could be placed in an equatorial orbit at a radius of 42200km. With this radius the satellite would have an orbital period equal to 24 hours. Give one advantage and one disadvantage of placing a weather satellite in a polar orbit rather than in the suggested equatorial orbit. (2) ……………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………
(ii) When planets align as they orbit the Sun they are said to be ‘in opposition’. The diagram shows the Earth and Jupiter in opposition.
A website states that the Earth and Jupiter are in opposition every 13 months. Deduce whether this statement is correct. mean distance from Earth to Sun = 1.5 × 1011m mean distance from Jupiter to Sun = 7.8 × 1011m TEarth = 12 months (5) …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………….. (b) The distance of Jupiter from the Sun varies from 7.4 × 1011m to 8.2 × 1011m. Calculate the change in gravitational potential energy of Jupiter as it moves from its closest distance to its furthest distance from the Sun. mass of Sun = 2.0 × 1030 kg mass of Jupiter = 1.9 × 1027 kg (3) …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………….
Question 13 : Jan 22
In the 17th century, Kepler proposed his ‘law of harmonies’ for planetary motion. This law suggested that the ratio of the square of the orbital period T to the cube of the mean radius R has the same value for all the planets that orbit the Sun. Mathematically his ‘law of harmonies’ can be written T2= KR ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………….
Question 17 : Jan 2023
In the 18th century, Cavendish carried out the first experiment to determine the gravitational constant G. The experiment used two lead spheres. (a) A physicist planned to investigate the gravitational force using lead spheres identical to the ones used in Cavendish’s original experiment. One of the spheres had a diameter of 30.5cm and a mass of 158kg. The second sphere had a diameter of 2.5cm and a mass of 0.73kg. The minimum force that could be measured by the physicist was 50μN. Deduce whether the physicist would be able to measure the gravitational force between the two spheres. (4) ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………… …
