# Class: 9th | Subject: Physics | Chapter: Gravitation

Class: 9th | Subject: Physics | Chapter: Gravitation

Time: 2 Hours | Maximum Marks: 60

Instructions:

All questions carry equal marks.
Write the answers in the provided space.
Section A: Multiple Choice Questions (1 mark each)

Which scientist is credited with formulating the law of universal gravitation?
a) Isaac Newton
b) Albert Einstein
c) Galileo Galilei
d) Johannes Kepler

If the mass of an object remains constant, what happens to its gravitational force when the distance between two objects is doubled?
a) It doubles.
c) It halves.
d) It becomes one-fourth.

What is the SI unit of gravitational force?
a) Newton
b) Kilogram
c) Joule
d) Meter

On which planet does an object weigh the most in our solar system?
a) Earth
b) Mars
c) Jupiter
d) Venus

What is the acceleration due to gravity on the surface of Earth (approximately)?
a) 10 m/s²
b) 9.8 m/s²
c) 6.67 x 10⁻¹¹ N m²/kg²
d) 1.62 m/s²

Section B: Short Answer Questions (2 marks each)

State Newton's law of universal gravitation and explain its components.

Why do astronauts appear weightless in space, even though they are still under the influence of Earth's gravity?

Define 'free fall' and explain how it relates to the motion of objects in a vacuum.

Section C: Long Answer Questions (5 marks each)

Calculate the gravitational force between two objects with masses of 50 kg and 70 kg separated by a distance of 10 meters. (Use Newton's law of universal gravitation)

Describe the factors that affect the value of gravitational acceleration on a planet. How does it differ on the Moon compared to Earth?

Explain why a satellite in orbit around Earth does not fall back to the surface. Include a discussion of orbital velocity and centripetal force.

Section D: Application-based Questions (5 marks each)

Imagine you are on a planet with half the mass of Earth but the same radius. Calculate the difference in the gravitational acceleration on this planet compared to Earth.

A spaceship is in deep space, far from any celestial body. If an astronaut inside the spaceship throws a ball, how will the motion of the ball differ from that on Earth? Explain.

Section E: Practical-Based Questions (5 marks each)

Describe an experiment to determine the value of 'g' (acceleration due to gravity) using a simple pendulum. Include the apparatus, procedure, and precautions.

Calculate the weight of an object with a mass of 25 kg on the surface of Mars, where the acceleration due to gravity is approximately 3.7 m/s².

Remember, this is just a sample question paper. You can adjust the difficulty and format according to the specific curriculum and requirements of the 9th-grade physics class.