CBSE - Class 9th - Science - Ch 10 - Gravitation - Question Bank

Hey friends, In this post we shall work towards preparing for the chapter 10th which is about Gravitation. In this chapter, you shall learn primarily about the concepts of Gravitation, the Laws of Gravitation and the way an object's motion is influenced on being acted upon by Gravitation.

CBSE - NCERT - Class 9th - Science

Chapter 10 - Gravitation

• What is Centripetal Force?

• As per Newton's third law of motion, to every action there is an equal and opposite reaction. Then why does an a falling apple gets attracted towards the earth and earth doesn't move towards the apple?

• State the Universal Law of Gravitation.

• Derive the mathematical equation governing the Universal Law of Gravitation.

• What is the significance of Gravitational Constant G? Give its value with SI Unit.

• Calculate the Force exerted by Moon on the Earth. Given - Mass of Moon is 7.4 x 10²² Kg and Mass of Earth is 6 x 10²⁴ Kg. Assume that they are separated by a distance of approx 4 x 10⁵ Km.

• What is acceleration due to gravity? Derive the mathematical expression for calculating gravity and calculate its value.

• A paper cup is dropped from a building roof top and it reaches ground in 2 second. Calculate the following:
• Its speed when it strikes the ground.
• Its average speed during the fall.
• The height of the building from where it was dropped.

• Calculate the velocity of the ball when it was thrown vertically upwards and reaches 40 m high before returning back and the time taken for the ball to reach that height.

• What is Weight? Give its SI Unit.

• The value you see while measuring an object in weighing machine is Mass or Weight of the object? Explain why.

• What is the weight of an object having 50 kg mass?

• If your mass is 60 Kg. Calculate your weight on earth and moon?

• What is Thrust?

• What is Pressure? Give its SI unit as well.

• A wooden cuboidal box having a mass of 10 kg with dimensions as 10 m x 20 m x 40 m is lying on bed. Calculate the pressure applied by the box on bed if it is made to lie with
• 10 m x 20 m surface as the base.
• 10 m x 40 m surface as the base.

• How does the concept of pressure applies to Liquids?

• Why does a ship made up of iron and steel does not sink in water while the same amount of metal in the form of iron blocks or sheet would sink instantly?

• What is Buoyant force?

• State the Archimedes Principle. What are its applications?

• You have a bag of cotton and a bag of iron each having a mass of 10 kg as measured in weighing machine. Even though the mass is same, in reality, one is heavier than another. Which one is that and why?

• Your mass shows 50 kg in weighing machine? Is your actual mass more or less than 50 kg as shown in weighing machine?

• Define Density?

• Define Relative Density with mathematical expression.

• What is the Relative Density of an Object when its density is 4000 kg m^-3. Given that density of water is 1000 kg m^-3.

Hope you found the above questions easy to understand and helpful for revision. If you would like to have more such questions or solutions to above questions, do let me know by commenting below.

CBSE - Class 9th - Science - Ch 9 - Force and Laws of Motion - Question Bank

In the previous post, we learnt about Motion as an introduction of Physics in Class 9th Science units. In this chapter we shall delve deeper into Physics by Learning more about the various laws of motion and its associated numerical calculations which shall help us build our foundation of Physics and associated mathematics for Class 11th later.

CBSE - Class 9th - Science

Chapter 9 - Force and Laws of Motion

• What is Force?

• How does an Object move? Why do they move?

• What are Balanced and Unbalanced Forces? Explain by giving examples.

• What is Friction and Friction Force?

• State Newton's First Law of Motion.

• What is Inertia? Why is First Law of Motion also referred to as Law of Inertia?

• Take a Glass, a Card and a five rupees coin. Place the Coin over the Card and the card on top of Glass. When the card is horizontally flicked fast with the finger, the coin placed over it falls in the tumbler instead of going with the card. Why?

• What is mass? How is it related to Inertia?

• Define Momentum. What is its SI Unit?

• State Newton's Second Law of Motion.

• Give the Mathematical formulation of Newton's Second Law of Motion.

• While trying to catch cricket ball, why does the fielder in the ground gradually pulls his hands backward along with the moving ball?

• A Force is applied from the back of a car of 500 kg at rest for 50 seconds to reach a velocity of 10 m/s. Calculate the force applied. If the same amount of force was applied for 25 seconds, what would have been the velocity of the car.

• Calculate the force needed to be applied to move:
• A Box of 10 kg at 3 m/s²
• A Box of 7 kg at 4 m/s²

• A Mini Truck weighing 1000 kg travelling at 72 km/h, applies brakes to stop. It took 5 second for it to come to rest. Calculate the amount of force exerted by the truck brakes.

• A force of 10 N can give a red color box an acceleration of 4 m/s². The same amount of force applied to a green box can give an acceleration of 5 m/s². Calculate the amount of acceleration that can be produced if both the object are tied together.

• State Newton's third law of motion.

• When a Gun is fired, why does the Shooter experiences some force pushing him backwards?

• What is the Law of conservation of momentum? Derive mathematical equation for the same.

• A Bullet weighing 20 g is fired from a Gun weighing 1 kg at a velocity of 100 m/s. Calculate the recoil velocity of the Gun.

• A Girl weighing 35 kg jumps with a horizontal velocity of 4 m/s over a stationary skating board weighing 5 kg. Assuming there is no other unbalanced force acting, what is their combined velocity as the skating board starts moving?

• Two cars approaching towards each other on road, collide at each other at high speed. After the collision, they got jammed to each other and both started moving in one direction for some time. The first car coming from Left side weighed 500 kg and had a velocity of 4 m/s. The second car coming from Right side weighed 800 kg and had a velocity of 2 m/s. Assuming the friction to be negligible, In which direction does both the cars move after their collision and at what velocity.

I hope these questions would help stay better prepared for exams. For solutions to the above questions, do comment below your thoughts and let me know.