Скачать или смотреть MCQs | Physics 9th | Chapter 5 | Gravitation | KPK Textbook Board, Peshawar | SLO Based

Q. Choose the best possible option.
Two masses are separated by a distance r. if both masses are doubled, the force of interaction between the two masses changes by a factor
(a) 2 (b) 4 (c) 1/2 (d) 1/4
The radius of earth is
(a) 9.8m (b) 6.67×〖10〗^(-11) m (c) 6×〖10〗^24 m (d) 6.4×〖10〗^6 m
The S.I unit for gravitational constant G is
(a) N〖kg〗^2 (b) Nm^2 〖kg〗^(-2) (c) Nm^2 〖kg〗^2 (d) Nm^(-2) 〖kg〗^2
What is the mass on planet Mercury of an object that weighs 784N on the Earth’s surface?
(a) 80.0kg (b) 118 (c) 784kg (d) More info needed
An object is orbiting a planet with orbital speed v, if the radius is same and mass is increased 4 times, by what factor orbital speed will change
(a) 2 (b) 4 (c) 1/2 (d) 1/4
The value of g at the surface of the moon is
(a) 9.8〖ms〗^(-2) (b) 1.63〖ms〗^(-2) (c) 4.9〖ms〗^(-2) (d) 8.9〖ms〗^(-2)
The value of g __________ with altitude
(a) increases (b) decreases (c) gets zero (d) remains the same
When a body is moved from sea level to the top of a mountain, there is change in the body’s
(a) mass (b) weight (c) none (d) both mass & weight
The value of g at equator is
(a) same at poles (b) larger at poles (c) smaller at poles (d) none
Q. Give a short response to the following questions
If there is an attractive force between all objects, why don’t we feel ourselves gravitating toward nearby massive buildings?
Does the sun exert a larger force on the Earth than that exerted on the sun by the Earth? Explain.
What is the importance of gravitational constant G? Why is it difficult to calculate?
If Earth somehow expanded to a larger radius, with no change in mass, how would your weight be affected? How would it be affected if Earth instead shrunk?
What would happen to your weight on earth if the mass of the earth doubled, but its radius stayed the same?
Why lighter and heavier objects fall at the same rate toward the earth?
The value of g changes with location on earth, however we take same value of g as 9.8〖ms〗^(-2) for ordinary calculations. Why?
Moon is attracted by the earth, why it does not fall on earth?
Why for same height larger and smaller satellites must have same orbital speeds?
Q. Solve the following numerical questions.
Pluto’s moon Charon is unusually large considering Pluto’s size, giving them the character of a double planet. Their masses are 1.25×〖10〗^22 kg and 1.9×〖10〗^21 kg, and their average distance from one another is 1.96×〖10〗^4 km. What is the gravitational force between them?
The mass of Mars is 6.4×〖10〗^23 kg and having radius of 3.4×〖10〗^6 m. Calculate the gravitational field strength (g) on Mars surface.
Titan is the largest moon of Saturn and the only moon in the solar system known to have a substantial atmosphere. Find the acceleration due to gravity on Titan’s surface, given that its mass is 1.35×〖10〗^18 and its radius is 2570 km.
At which altitude above Earth’s surface would the gravitational acceleration be 4.9〖ms〗^(-2)?
Assume that satellite orbits Earth 225km above its surface. Given that the mass of Earth is 6×〖10〗^24 kg and the radius of Earth is 6.4×〖10〗^6 m, what is the satellite’s orbital speed?
The distance form center of earth to center of moon is 3.8×〖10〗^8 m. Mass of earth is 6×〖10〗^24 kg. What is the orbital speed of moon?
The Hubble space telescope orbits Earth (m_e=6×〖10〗^24 kg) with an orbital speed of 7.6×〖10〗^3 〖ms〗^(-1). Calculate its altitude above Earth’s surface.