Gravitation ( 9th standard)

Introduction to Gravitation

Gravitation is one of the 4 fundamental forces in nature in addition to the electromagnetism, the strong nuclear force, and the weak nuclear force. It is the force of attraction that acts between the 2 bodies of different masses in the universe. In this lesson, we shall discuss the gravitation, the universal Laws of Gravitation, motion of objects under the influence of gravitational force on the earth. We will also enlighten the concepts og mass, weight, free fall, escape velocity etc. The terms gravitation and gravity are used synonymously. It is the force of attraction between any two bodies.

Nature of gravitational force

None of the bodies can exist in a fixed path in the absence of gravity. We are all existing on the surface of the earth instead of being in the space because of gravitation. Every object in the universe has some influence towards the gravity of other object surrounding it. Gravitation is not same for all the bodies because of the differences in the masses in them. Therefore, gravitation has very close correlation with the mass of the object. The force of attraction also depends upon the distance between 2 or more bodies. Some of the features of gravitational force are:

1. It is a non-contact force – it acts even without the objects touching.
2. It is a mutual force – both objects pull on each other equally (Newton’s Third Law).
3. It is always attractive, never repulsive
4. It acts invisibly across space, and though weak, it dominates at astronomical scales.

Some examples of gravity are:

1. Objects Falling to the Ground.For example, when you drop a ball, it falls because Earth’s gravity pulls it downward.
2. Weight of a Person is nothing but the gravitational force Earth exerts on your body.
3. Tides in Oceans is also caused by the gravitational pull of the Moon (mainly) and the Sun on Earth’s oceans.
4. Gravity keeps us on the surface of floor, without it, we might float like astronauts in space.

 Types of Forces:

There are four major forces in the universe, they are:

1. Gravitational Force
2. Electromagnetic Force
3. Strong Nuclear Force
4. Weak Nuclear Force

1. Gravitational Force is the weakest of the four fundamental forces, but despite being weak at the atomic level, it becomes significant for massive objects like stars, planets, and galaxies. Gravity is always attractive in nature.
2. Electromagnetic Force acts between electrically charged particles. It is a combination of electric and magnetic forces. It can produce both attractive or repulsive forces depending on the type of charges involved. It is much stronger than the gravity and it is responsible for most of the forces we experience in out=r daily life, such as friction, tension, current, heat etc.
3. Strong Nuclear Force is the strongest of all four forces. It acts between the subatomic particles that bind atoms . The force also holds protons and neutrons together inside the atomic nucleus. It acts only at very short distances (around 10−1510^{-15}10−15 meters).
4. Weak Nuclear Force is rsponsible for processes like beta decay in radioactive elements. It acts between elementary particles and is weak compared to the strong force but still stronger than gravity.It operates at very short ranges.

Newton’s Law of Universal Gravitation

Before Newton, people knew that objects fall to the ground (thanks to gravity), and that celestial bodies like the Moon and planets move in predictable paths—but no one explained about the phenomena under a single law. In 1687, Sir Isaac Newton proposed the Law of Universal Gravitation in his book Principia Mathematica. He was the first to suggest that "The same force that causes an apple to fall from a tree also governs the motion of the Moon and planets." This was revolutionary as Newton meant that gravity wasn’t just an Earth-bound phenomenon but a universal force acting everywhere in the cosmos. Newton’s Law of Universal Gravitation states that "Every object in the universe attracts every other object with a force that is directly proportional to the product of their masses, and inversely proportional to the square of the distance between their centers."

 Mathematical Expression:

F=G m₁*m₂/r^2, where:

Symbol	Meaning
F	Gravitational force between two objects (Newtons, N)
G	Gravitational constant = 6.673×10−11 Nm2/kg2
m1 and m2	Masses of the two objects (kg)
r	Distance between the centers of the masses (m)

Gravitational Constant

Gravitational Constant “G” was first measured by Henry Cavendish in 1798. Its small value “g” shows that gravity is a very weak force compared to others (like electromagnetism), which is why we only feel it with large masses (like Earth).

Real-World Applications of Newton`s Gravitation law

1. Falling Objects: Apples, stones, or anything that drops – all are pulled by Earth’s gravity.
2. Planetary Orbits: Planets stay in orbit around the Sun due to the gravitational force acting as a centripetal force.
3. Tides: Gravitational pull of the Moon (and Sun) causes ocean tides on Earth.
4. Satellite Motion: Artificial satellites stay in orbit because Earth's gravity pulls them toward its center, while their forward motion keeps them in a circular or elliptical path.
5. Weight: Your weight is the gravitational force Earth exerts on your body: W=mg
6. Black Holes: Form when gravity becomes so strong that not even light can escape.

Acceleration Due to Gravity?

When you drop something (like a ball or a pencil), it falls down because the Earth pulls it toward the ground. This pull is called gravity. The acceleration due to gravity means, how fast something speeds up when it's falling freely. It is written as the letter g. On the earth, the value of g is about 9.8 meters per second squared (m/s²). This means, every second, a falling object goes 9.8 m/s faster than the second before. So: After 1 second: it’s falling at 9.8 m/s. After 2 seconds it falls at 19.6 m/s, and after 3 seconds, the same object falls at 29.4 m/s and so on… Different planets have different "g" values, such as

Planet	g (approx.)
Earth	9.8 m/s²
Moon	1.6 m/s²
Mars	3.7 m/s²
Jupiter	24.8 m/s²

Moon’s Revolution around Earth due to gravity

As the Newton’s Law of Gravitation states that every object with a certain mass attracts every other object with a different mass. Earth, having a much larger mass, pulls the Moon towards it which prevents the Moon from flying off into the space. The Moon has a natural forward velocity (inertia) as it is strongly captured by the earth. Without gravity, moon would have moved in a straight line, but, Earth’s gravity constantly pulls it inwards which makes moon falls around the Earth. This will create a path called orbit. In other words, Moon is in a continuous state of free fall toward Earth. Because of the forward motion influenced by the earth , moon travels at nearly constant speed . The balance between the Moon’s inertia and Earth’s gravity results in a stable centripetal force with an elliptical orbit (almost circular). Centripetal force means , when a body undergoes circular motion, it experiences a force that acts towards the centre of the circle. Centripetal force is given by the following equation:

Centripetal force= Mass X Speed^2/Distance to center^., I,e c=mv²/r

Free Fall and Motion

Free fall is a type of motion where an object moves under the influence of gravity alone, without any air resistance or other forces acting on it. In free fall, the object accelerates downward at a rate of approximately 9.8 meters per second squared (m/s²) on Earth. This means its speed increases steadily as it falls. Free fall is a special kind of motion that shows how gravity affects objects regardless of their mass. For example, if you drop a ball from a height, it will start slow but fall faster and faster each second due to gravity pulling it toward the ground. This motion is predictable and follows the laws of physics, making it an important concept in understanding how things move under gravity. The sign of convention of free fall due to gravity g is positive when an object is moving towards earth and it is –ve when moves away from earth.

Weight and Mass

Mas is the amount of matter in an object. It does not change no matter where you are (Earth, Moon, space). It is measured in kilograms (kg) and it is a scalar quantity (only has magnitude, no direction). But weight is the force of gravity acting on an object’s mass. Weight depends on the location, because gravity varies (e.g., you weigh less on the Moon). Wight is measures in Newtons (N). Weight is a vector quantity because it has both magnitude and direction — always toward the center of the planet). The relation between weight and mass is expressed as Weight = Mass X Gravity ( W=mg), where g is a constant around 9.8m/s (g≈9.8 m/s). Weight changes between different celestial bodies but the mas remains constant

Thrust and Pressure

Thrust is a force that pushes an object forward. It is often used when talking about rockets, engines, or jets. It acts in the opposite direction of resistance (like air or gravity). For example, when a rocket fires its engines, the gases are pushed downward, and the rocket is thrust upward. Pressure is the force applied on a surface per unit area. It tells us how concentrated a force is over an area. The relationship between thrust and pressure is expressed as Pressure= Thrust/Area

Fluid pressure

Fluid pressure is the pressure exerted by a liquid or gas in all directions within a container or space. It occurs because the particles in a fluid are constantly moving and colliding with each other and the walls of their container. In liquids, the pressure increases with depth because the weight of the fluid above pushes down on the fluid below. Fluid pressure depends on three main factors: the density of the fluid, the depth (or height) of the fluid column, and the acceleration due to gravity.

The formula for fluid pressure is: Pressure=density×gravity×height(P=ρgh)

Up thrust or buoyant force

Buoyant force is the upward force that a fluid (like water or air) exerts on any object placed in it. This force is what makes objects float or feel lighter in water. When you put an object into a fluid, it pushes some of the fluid out of the way (this is called displacement). In response, the fluid pushes back upward on the object — this upward push is the buoyant force. The strength of the buoyant force depends on the weight or density of the fluid displaced by the object. This is described by Archimedes’ Principle, which says that Buoyant Force=Weight of Displaced Fluid. If the buoyant force is greater than the object's weight, the object floats. If it’s less, the object sinks. That’s why a heavy ship made of steel can float — it displaces enough water to balance its own weight.

Relative Density

Relative Density (also called specific gravity) is a way to compare how heavy a substance is compared to water. It tells us how many times heavier or lighter a material is compared to the same volume of water. It is written as, Relative Density= Density of Substance/Density of water.

TEXTBOOK QUESTION ANSWERS

Question 1. State the universal law of gravitation.
Answer:  Every object in the universe pulls on every other object with a force called gravity. This force gets stronger if the objects are heavier, and weaker if they are farther apart. In other words, the bigger the masses, the stronger the pull between them, but the farther away they are, the weaker the pull becomes. This force of attraction acts between all things, no matter how big or small, everywhere in the universe. Gravitational force = (a constant number) × (mass of the first object) × (mass of the second object) ÷ (distance between them) squared., it is expressed as F= M X m/ d²

Question 2. Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.

Answer: F=G*m_1*m₂/d²

Question 3. What do you mean by free fall?
Answer: Free fall means that an object is falling only under the influence of gravity, with no other forces (like air resistance) acting on it.

Question 4. What do you mean by the acceleration due to gravity?
Answer: Acceleration due to gravity is the rate at which an object speeds up as it falls freely toward the Earth (or any planet), due to the force of gravity. On Earth, this acceleration is approximately: ??= 9.8 m/s so, g is a constant around 9.8m/s

Question 5. What are the differences between the mass of an object and its weight?
Answer:

Mass	Weight
Mass is the amount of matter in an object.	Weight is the force of gravity acting on that mass.
It is always the same, no matter where you are.	It changes depending on the gravity of the place (Earth, Moon, etc.).
Measured in kilograms (kg).	Measured in newtons (N).
It is a scalar quantity (has no direction).	It is a vector quantity (has direction — toward the center of gravity).
Measured using a balance.	Measured using a spring scale.
Mass	Weight
Mass of an object is the measure of the inertia.	The weight of an object is the force with which it is attracted to the earth.

Question 6. Why is the weight of an object on the moon l/6th its weight on the earth?
Answer: The weight of an object on the Moon is 1/6th of its weight on Earth because the Moon’s gravity is much weaker than Earth’s. Weight depends on gravity, using the formula:

Weight=Mass × Gravity, the Moon has less mass and a smaller size than Earth. As a result, the Moon’s gravitational pull is about 1/6th of Earth’s. Gravity on the earth is 9.8 m/s² whereas gravity on the Moon is only 1.6 m/s² which is 6 times smaller than the earth`s gravity.

Question 7. Why is it difficult to hold a school bag having a strap made of a thin and strong string?
Answer: It is difficult to hold a school bag having a starp made of a thin and strong string because the area and starp is small. Hence large pressure is exerted by the starp on the fingers.

Question 8.What do you mean by buoyancy?
Answer: Buoyancy is the upward force that a fluid (like water or air) exerts on an object placed in it. This force acts against gravity and makes objects feel lighter in a fluid. In simple words, when you put something into water, the water pushes up This upward push is called buoyancy or buoyant force. It's the reason why boats float, and why you feel lighter when you're in a swimming pool.

Question 9. Why does an object float or sink when placed on the surface of the water?
Answer: Upward thrust of liquids, (different-in liquid densities) Sink of an object depends upon density. The density of an object is more than water then it sinks. Object density is less than that of water it floats.

Question 10. You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
Answer: Our mass is more than 42 kg.

Question 11. You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than the others. Can you say which one is heavier and why?
Answer: Iron bar is heavier than the cotton bag because for the mass the iron bar will have a lesser surface area and apply more force, so the iron bar is heavier than a cotton bag.

Textbook Exercises

Question 1. How does the force of gravitation between two objects change when the distance between them is reduced to half?
Answer: When the distance between two objects is reduced to half, the gravitational force between them becomes four times stronger. This is because gravitational force depends on the square of the distance between the objects. So, if the distance becomes half, the force becomes 1 divided by square of

2,=(1/2)², which is 1 ÷ 1/4 = 4 times more. In simple terms, bringing objects closer increases the gravitational pull between them very quickly.

i.e. the force of gravitation becomes 4 times than the original value.

Question 2. Gravitational force acts on all objects in proportion, to their masses. Why then a heavy object does not fall faster than a light object?
Answer: Each object falls towards the earth with the acceleration equal to the acceleration due to gravity, which is constant (9.8ms^-2) and does not depend on the mass of the object. So heavy object does not fall faster than the light object.

Question 3.What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface? (Mass of the earth is 6 x 10²³ kg and radius of the earth
6.4 x 10⁶m)

To find the gravitational force between the Earth and a 1 kg object on its surface, we use the formula:

Force (F) = (G × M × m) ÷ R²

Where:

• G is the gravitational constant = 6.674 × 10?¹¹ N·m²/kg²
• M is the mass of the Earth = 6 × 10²³ kg (as given)
• m is the mass of the object = 1 kg
• R is the radius of the Earth = 6.4 × 106 m

Substitute the values:

F = (6.674 × 10?¹¹ × 6 × 10²³ × 1) ÷ (6.4 × 106)²
F ≈ (40.044 × 10¹²) ÷ (40.96 × 10¹²)
F ≈ 0.978 Newtons

Final Answer: The gravitational force between the Earth and a 1 kg object is approximately 0.978 N.

Question 5. If the moon attracts the earth, why does the earth not move towards the moon?
Answer:
The Earth does not move towards the Moon because the Moon's gravitational pull is counteracted by the Earth's enormous mass, which results in negligible acceleration for the Earth. While both bodies exert an equal and opposite gravitational force on each other, as stated by Newton's third law, Newton's second law of motion,F=ma, shows that acceleration is inversely proportional to mass a=F/m. Because the Earth's mass is so much greater than the Moon's, the resulting acceleration of the Earth is extremely small and imperceptible. 

Question 6.
What happens to the force between two objects, if
i) the mass of one object is doubled?
ii) the distance between the objects is doubled and tripled?
iii) The masses of both objects are doubled?
Answer:

1. The mass of one object is doubled?
   The gravitational force also doubles. This is because the force is directly proportional to the mass. So if one mass becomes twice as big, the force becomes 2 times stronger. F=Gm₁*m₂/r²

1. The distance between the objects is doubled and tripled?

If the distance is doubled, the gravitational force becomes 1/4th as strong. If the distance is tripled, the gravitational force becomes 1/9th as strong. This happens because force is inversely proportional to the square of the distance. So, increasing the distance reduces the force by the square of that factor.

iii) The masses of both objects are doubled?
The gravitational force becomes 4 times stronger. This is because if both masses are doubled, the force becomes proportional to 2 × 2 = 4 times the original force.

Question 7. What is the importance of universal law of gravitation?
Answer:

The Universal Law of Gravitation is important because it explains how every object in the universe attracts every other object with a force called gravity. This law helps us understand many natural phenomena, such as:

1. Why planets orbit the Sun and moons orbit planets.
2. How tides are caused by the gravitational pull of the Moon and the Sun on Earth’s oceans.
3. Why objects fall to the ground instead of floating away.
4. The behaviour of stars, galaxies, and the motion of celestial bodies throughout the universe.
5. It helps scientists calculate gravitational forces, predict planetary movements, and even send spacecraft to other planets.

Question 9.What do we call the gravitational force between the earth and an object?

Answer: The gravitational force between the earth and an object is called the force of gravity.

Question 10. Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator will the friend agree with the weight of Gold bought? If not, why? (Hint: The value of g is greater at the poles than at the equator)

Answer: Weight of an object, W = mg.
where g = acceleration due to gravity.
The value of g is greater at the poles than at the equator. So the weight of the gold at the equator will be less than the weight of the gold at poles. So Amit’s friend will find the weight of the gold less than the weight told by Amit.

Question 11. Why will a sheet of paper fall slower than one that is crumpled into a ball?
Answer:
The sheet of paper falls slower than that is compelled into a ball because in the first case the area of the sheet is more. So it experiences a large opposing force due to air. while the sheet crumpled into a ball experience less opposing force due to small area.

Question 12. The gravitational force on the surface of the moon is only 1/6 as strong as gravitational force on the earth. What is the weight in newtons of a 10 kg object on the moon and on the earth?
Answer:
Mass of the object m = 10 kg.
Weight on the earth W = mg.
= 10 × 9.8 = 98 N
Weight on the moon = 1/6 of the weight on the earth.
= 1 × 98 = 16.33 N
= 16.33 N.

Question 13.
A ball is thrown vertically upwards with a velocity of 49m/s. Calculate.
i) the maximum height to which it rises.
ii) the total time it takes to return to the surface of the earth.
Answer:

A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate:

1. i) The maximum height to which it rises.
   ii) The total time it takes to return to the surface of the Earth.

Given:
Initial velocity, u = 49 m/s
Acceleration due to gravity, g = 9.8 m/s²
Final velocity at maximum height, v = 0 m/s

1. i) Maximum height reached (h):

Using the equation of motion:
v² = u² - 2gh

Rearranged to find h:
h = (u² - v²) ÷ (2g)

Substitute the values:
h = (49² - 0²) ÷ (2 × 9.8) = 2401 ÷ 19.6 = 122.5 meters

1. ii) Total time to return to the surface:

Time to reach maximum height (t_up):
v = u - g × t_up

Rearranged for t_up:
t_up = (u - v) ÷ g = (49 - 0) ÷ 9.8 = 5 seconds

Total time of flight (t_total) is twice the time going up:
t_total = 2 × t_up = 2 × 5 = 10 seconds

Final answers:

• Maximum height = 122.5 meters
• Total time to return = 10 seconds

Question 14. A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground.

Answer:
Given: Height (h) = 19.6 meters, Initial velocity (u) = 0 m/s (since the stone is released)
Acceleration due to gravity (g) = 9.8 m/s²

Using the equation:
Final velocity squared = Initial velocity squared + 2 × g × h

Substitute the values:
Final velocity squared = 0 + 2 × 9.8 × 19.6 = 384.16

Take the square root to find the final velocity:
Final velocity = √384.16 = 19.6 m/s

Answer:
The final velocity just before the stone hits the ground is 19.6 m/s.

Question 15. A stone is thrown vertically upward with an initial velocity of 40m/s. Taking g = 10m/s, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?

Answer: Initial velocity u = 40 ms^-1
At maximum height, final velocity becomes zero i.e., v = 0
From equation of motion, v² = u² – 2gh
(0)² = (40)² – 2 × 10 × h
0 = 1600 – 20h
Total time taken by the ball to return to surface of the earth = 5 + 5 = 10s.
∴ h = 1600/20 = 80 m
Maximum height reached by the stone = 80 m
After reaching the maximum height, the stone will fall towards the earth and will reach the earth surface covering the same distance.
So distance covered by the stone
= 80 + 80 = 160 m
Displacement of the stone = 0
(because the stone starts from the earth surface and finally reaches the earth surface again i.e the initial and final position of the stone are same

Question 16. Calculate the force of gravitation between the earth and the sun, given that the mass of the earth = 6 × 10²⁴kg and of the sun = 2 × 10³⁰ kg. The average distance between the two is 1.5 × 10¹¹m)
Answer:
Given: Mass of Earth = 6 × 10^24 kg, Mass of Sun = 2 × 10^30 kg, Distance between Earth and Sun = 1.5 × 10^11 m
, ravitational constant, G = 6.674 × 10^-11 N·m²/kg²

Formula used:
Force (F) = (G × mass of Earth × mass of Sun) ÷ (distance)²
F = (6.674 × 10^-11 × 6 × 10^24 × 2 × 10^30) ÷ (1.5 × 10^11)²
F = (6.674 × 6 × 2 × 10^(-11 + 24 + 30)) ÷ (1.5)² × 10^(22)
F = (80.088 × 10^43) ÷ (2.25 × 10^22)
F = 35.6 × 10^21 N
Or, F = 3.56 × 10^22 Newtons

Question 17.
A stone is allowed to fall from the top of a tower 100m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25m/s. Calculate when and where the two stones will meet.

Given:
Height of tower = 100 m
Initial velocity of stone dropped from top = 0 m/s
Initial velocity of stone projected upwards = 25 m/s
Acceleration due to gravity = 9.8 m/s²
Time after release = t seconds
Height where they meet = x meters from the ground

Step 1: Position of stone dropped from the top after time t
Distance fallen = s1 = 0 + (1/2) × 9.8 × t² = 4.9 t² meters
Height from ground = 100 - 4.9 t² meters

Step 2: Position of stone projected upwards after time t
Distance risen = s2 = 25 t - (1/2) × 9.8 × t² = 25 t - 4.9 t² meters
Height from ground = 25 t - 4.9 t² meters

Step 3: At meeting point, heights are equal
100 - 4.9 t² = 25 t - 4.9 t²
Simplify: 100 = 25 t
Solve for t: t = 100 ÷ 25 = 4 seconds

Step 4: Find the meeting height
Height = 25 × 4 - 4.9 × 4² = 100 - 78.4 = 21.6 meters

Answer: The stones meet after 4 seconds at 21.6 meters above the ground.

Question 18. A ball thrown up vertically returns to the thrower after 6s. Find
a) the velocity with which it was thrown up
b) the maximum height it reaches, and
c) its position after 4s.
Answer:
Given: Total time of flight = 6 seconds and Acceleration due to gravity = 9.8 m/s²

9. a) Velocity with which it was thrown up
   Time to reach maximum height = total time ÷ 2 = 6 ÷ 2 = 3 seconds
   Using v = u - g × t and v = 0 at maximum height,
   0 = u - 9.8 × 3
   So, u = 9.8 × 3 = 29.4 m/s
10. b) Maximum height reached
    Using h = u × t - (1/2) × g × t²
    h = 29.4 × 3 - 0.5 × 9.8 × 3²
    h = 88.2 - 44.1 = 44.1 meters
11. c) Position after 4 seconds
    Using s = u × t - (1/2) × g × t²
    s = 29.4 × 4 - 0.5 × 9.8 × 4²
    s = 117.6 - 78.4 = 39.2 meters above the thrower

Question 19. In what direction does the buoyant force on an object immersed in a liquid act?
Answer: The buoyant force on an object immersed in a liquid always act in upward direction.

Question 20. Why does a block of plastic released under water come up to the surface of water.
Answer: The buoyant force on an object immersed in a liquid always act in upward direction.

Question 21.
The volume of 50g of a substance is 20 cm³. If the density of water is 1gcm^-3 will the substance float or sink?
Answer:
Given: Mass of substance = 50 g and Volume of substance = 20 cm³ and Density of water = 1 g/cm³

Step 1: Calculate the density of the substance
Density = Mass ÷ Volume
Density = 50 g ÷ 20 cm³ = 2.5 g/cm³

Step 2: Compare density of substance with density of water
Density of substance (2.5 g/cm³) is greater than density of water (1 g/cm³).

Conclusion: Since the substance is denser than water, it will sink.

Question 22. The volume of 500g sealed packet is 350 cm^-3, will the packet float or sink in water if the density of water is 1gmcm^-3? What will be the mass of the water displaced by this packet?
Answer:
Given: Mass of packet = 500 g, Volume of packet = 350 cm³ and Density of water = 1 g/cm³

Step 1: Calculate the density of the packet
Density = Mass ÷ Volume
Density = 500 g ÷ 350 cm³ ≈ 1.43 g/cm³

Step 2: Compare densities
Density of packet (1.43 g/cm³) is greater than density of water (1 g/cm³), so the packet will sink.

Step 3: Calculate the mass of water displaced
Mass of water displaced = Volume of packet × Density of water
Mass of water displaced = 350 cm³ × 1 g/cm³ = 350 g

Final answers: The packet will sink in water and the mass of water displaced by the packet is 350 grams.