Final answer:
Climate change is primarily driven by the emission of greenhouse gases like carbon dioxide and methane, mainly from the burning of fossil fuels, deforestation, agriculture, and manufacturing. Human-caused factors are the most significant contributors to the current rates of global warming, surpassing natural influences on the climate.
Explanation:
One significant factor contributing to climate change is the emission of greenhouse gases such as carbon dioxide (CO2) and methane. The largest driver of warming comes from burning fossil fuels like coal, oil, and natural gas, which is the main source of CO2 emissions. This is further compounded by deforestation, agriculture, and manufacturing. Other manmade causes include increases in near-surface ozone from internal combustion engines, and aerosols such as carbon black and dust, which impact the Earth's albedo and its ability to reflect solar radiation.
It is essential to distinguish between natural factors that have historically influenced climate, such as changes in Earth's orbital patterns, plate tectonics, solar output, and volcanic activity, versus the anthropogenic (human-caused) factors driving the current unprecedented rates of climate change. Human-related factors far outweigh natural influences, which cannot fully explain the rapid increase in global temperatures observed today. The use of fossil fuels for energy and transportation is identified as the critical factor in fueling the current trend of climate change, contributing directly to the greenhouse effect.
Efforts to reduce emissions, transition to renewable energy sources, and implement more sustainable practices are vital steps in addressing the ongoing climate crisis. This reflects a dire need for coordinated global action to mitigate the impacts on food supply, water resources, ecosystems, and human health.
why generally metals are good conductor and non metals are bad conductor of electricity
Metals - The close packing of the metal ions in the lattice and the delocalised electrons ensure it can carry kinetic energy through the lattice.
Non - metals have fewer free electrons and electrons are held tightly, meaning they're not allowed to move freely.
Final answer:
Metals are good electrical conductors due to their free electrons that allow for easy flow of charge, while non-metals are poor conductors as their electrons are more tightly bound. This electron structure difference makes metals suitable for electrical wiring and non-metals for insulation.
Explanation:
Metals are generally good conductors of electricity because they have free electrons that can move easily between atoms, providing a path for electrical charge to flow. This is why metals like copper and gold are commonly used in electrical conducting wires. On the other hand, non-metals are typically poor conductors of electricity, as their electrons are more tightly bound to their atoms and do not move freely. Materials like plastic, wood, and glass are examples of non-conductors or insulators. Therefore, the fundamental distinction between metals and non-metals in terms of conductivity is based on how their electrons are structured and interact.
Properties of Metals and Nonmetals
Metals have a shiny lustre, are malleable and ductile, making them ideal for making jewellery and cooking utensils.
Non-metals, such as sulfur and oxygen, are neither malleable nor ductile, and they usually do not conduct heat and electricity well.
Moving beyond electrical conductivity, materials can also be classified by magnetism, thermal conductivity, and other properties, emphasizing the versatility and range of uses for different elements based on their conducting abilities.
PLEASE ANSWER!!!!!
nova, whose mass is 50.0kg, stays out skiing for too long and her body temperature drops by 2.00 degrees celcius. what is the amount of heat lost from novas body? (human body = 3470J/kg degrees celcius)
Use the equation q=mc/\T, where q is the heat lost, m is mass, and /\T is the change in temperature, and c is the specific heat.
q=50kg(3470J/kg K)(2K)
q=347000 J
Any other questions, just ask.
The heat lost from Nova's body is calculated using the specific heat formula Q = mcΔT. Substituting in the given values, we find that Nova's body lost 347,000 joules of heat.
Explanation:The amount of heat lost by Nova's body can be calculated using the specific heat formula which is: Q = mcΔT, where 'Q' is the heat transferred, 'm' is the mass, 'c' is the specific heat, and 'ΔT' is the change in temperature. In this case, you would substitute the given values into this formula: Q = (50.0kg) * (3470J/kg°C) * (2.00°C)
When you multiply these together, the resulting heat loss is 347,000 joules. Therefore, Nova's body lost 347,000 joules of heat while she was skiing.
Learn more about Heat Lost here:https://brainly.com/question/16170617
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A garage door opener has a component that stop the door from coming down if something is in the way. This component is made up of a laser light on one side and a receiver on the other. Which best explains why this component works.
A) The receiver collects the laser light indicating that something is in the way.
B) Any object blocking the path of the laser will reflect the beam into the reciever.
C) Any object in its path changes the color of the laser before it gets to the reciever.
D) The laser light travels in a straight line towards the receiver, an object in the way blocks this straight line path.
The wavelength of a sound will give us information about________________.
A) how loud the sound will be
B) what produced the sound
C) the high or low pitch of the sound
D) the speed of sound
Which statement about how sound travels is true?
A) The speed of sound is the same at all times.
B) The speed of sound depends on the material it travels through.
C) Sound vibrations only move through a vacuum.
D) Sound moves faster through insulators than conductors.
Which statement about the electromagnetic spectrum is false?
A) There are wavelengths other than those of visible light in the spectrum.
B) Microwaves have a longer wavelength than visible light.
C) The higher the energy of the wavelength, the more dangerous they are.
D) Infrared light waves are visible.
laser in the garage . . . D
wavelength of a sound . . . C
how sound travels . . . B
electromagnetic spectrum . . . D
Final answer:
The garage door safety mechanism functions by blocking a laser beam, which triggers the system to halt the door. The wavelength of sound informs us about pitch, with longer wavelengths corresponding to lower pitches. The speed of sound is dependent on the medium it travels through, and infrared light waves are not visible to the human eye.
Explanation:
The component that prevents a garage door from closing if there is an obstruction works as follows: The laser light travels in a straight line towards the receiver, and if an object blocks this path, the door will not close. The correct answer is D. An object in the path interrupts the beam, which signals the system to stop the door.
Regarding sound waves, the wavelength of a sound provides information about the pitch of the sound, which means C is the correct answer. A longer wavelength correlates with a lower pitch, and vice versa.
The speed of sound does not remain constant and varies depending on the material through which it travels, making B the correct statement. This variability is due to differences in density and elasticity of different media.
In the electromagnetic spectrum, D is the false statement because infrared light waves are not visible to the human eye. The electromagnetic spectrum includes a range of wavelengths, some visible and some not, such as infrared.
a player passes a 0.600kg basketball down court for a fast break.the ball leaves the player hands with a speed of 8.30m/s and slows down to 7.20 m/s at its highest point. Ignoring air resistance,how high above the release point it is at its maximum height?
At the release point, the ball has kinetic energy,
[tex]\dfrac12m{v_0}^2[/tex]
and at its maximum height it has potential and kinetic energy,
[tex]-mgy+\dfrac12mv^2[/tex]
where [tex]y[/tex] is the maximum height attained above the release point.
The LoCoE tells us that we should have
[tex]\dfrac12m{v_0}^2=-mgy+\dfrac12 mv^2[/tex]
[tex]\implies v^2-{v_0}^2=-2gy[/tex]
[tex]\implies\left(7.20\dfrac{\rm m}{\rm s}\right)^2-\left(8.30\dfrac{\rm m}{\rm s}\right)^2=-2\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)y[/tex]
[tex]\implies y=0.870\,\mathrm m[/tex]
Answer: The maximum height of the ball is 0.87 m
Explanation:
To calculate the height of the ball, we use third equation of motion:
[tex]v^2-u^2=2as[/tex]
where,
s = distance traveled / height of the ball = ?
u = initial velocity of the ball = 8.30 m/s
v = final velocity of the ball = 7.20 m/s
a = acceleration due to gravity = [tex]-9.8m/s^2[/tex] (negative sign represents the ball is going upwards that is against gravity)
Putting values in above equation, we get:
[tex](7.20)^2-(8.30)^2=2\times (-9.8)\times s\\\\s=\frac{(7.20)^2-(8.30)^2}{(2\times (-9.8))}=0.87m[/tex]
Hence, the maximum height of the ball is 0.87 m
what is the weight of 0.12kg mass?
1.1772 N
Step by Step ExplanationGiven in the question,
mass of an object = 0.12 kg
To find the weight of this object we will use formula
weight = mass x acceleration due to gravity
We know that acceleration due to gravity on earth is constant = 9.81 m/s²
So,
weight = 0.12 x 9.81
= 1.1772 N
Since it is not mention that were the object is so i assume that it is on earth but if it is on moon then acceleration due to gravity will be 1.625 m/s²
PLEASE HELP ASAP!!
Dan wants to lift his car using a moveable pulley system like the one shown in the picture.
Using a moveable pulley system will decrease the force needed to lift the car by increasing the
A. Distance over which the force is applied.
B. Strength contained in Dan’s arms.
C. Total mass of Dan’s arms.
D. Total mass of the car.
Answer:
A. Distance over which the force is applied
Explanation:
As we know that in pulley system the mass of the car is balanced by the tension in the string
so here we will have
[tex]T = r \times F[/tex]
so here in order to decrease the force needed to lift the car we have to increase Distance over which the force is applied
So here if we increase the distance over which force is applied then it will reduce the effort applied by us in this pulley system as the torque will be more if the distance is more.
which term describes the number of thoughs that pass a point in a given amount of time
The term that describes the number of thoughs that pass a point in a given amount of time is FREQUENCY.
In wave theory, frequency refers to the number of wave that pass through a fixed point in a given amount of time. Frequency is usually measure in Hertz. The mathematical formula for finding frequency is:
F = Velocity of wave / wavelength of wave.
7. A rock is projected upward from the surface of the moon, at time t = 0.0 s, with a velocity of The acceleration due to gravity at the surface of the moon is What is the maximum height of the rock above the surface?
278 m
202 m
245 m
115 m
125 m
The maximum height of the rock above the surface is 202 m
All the elements of a family in the periodic table have what feature in common?
They all have the same number of electrons in the electron cloud.
Please help! last test of the week, and i can have a long weekedn! Friday and Sun and Sat.
It must have a medium to travel through.
Happy to help. Marking me the brainliest would really be appreciated.
what causes the phases of the moon as seen from earth brainly
From the Earth, we can see multiple phases of the Moon in a 28 days cycle. These phases are not changes int he Moon or how much of it is lightened, but instead it is a result of the positions that the Earth, Moon, and Sun have in relation to each other. The Sun is always lighting one half of the Moon, which is the half that is turned toward it. From the Earth it doesn't seem that way, as we can see Moon that seems fully light, partially light on the left side, partially light on the right side, or totally dark, but all of that depends on how much of the lighted side of the Moon is turned toward the Earth.
A sodium has an atomic number of 11 and the atomic mass of 23. Determine the its proton, electrons, and neutrons
The mass number of an element tells us the number of protons AND neutrons in an atom (the two particles that have a measurable mass). Sodium has a mass number of 23amu. Since sodium has 11 protons, the number of neutrons must be 23 – 11 = 12 neutrons.
Normal force is exerted _____to the surface of an object.
A. perpendicular
B. 45 degrees
C. horizontal
The normal force is always (underline, bold) is always perpendicular to the surface an object is sitting on. If the object is on an inclined plane, then the normal will not be vertical but it will be perpendicular to the angle of the incline.
The diagram below (left) shows a normal force (GH) that is not vertical, but it is perpendicular to the surface. The object on the right is the more usual normal a mass on a table top.
The vertical line on the right is the normal and it points up.
The correct option is A. perpendicular
Explanation:In Physics, the normal force is the component of a contact force that is perpendicular to the surface that an object contacts. It is the support force exerted upon an object that is in contact with another stable object. Normal Force will be always acting opposite to the force falling on the surface. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book.
What is the relationship between the buildup of electons and the sudden flow of electrons from one charged object to another?
Static electricity
hope this helps :)
the answer to this question is static electricity
Two common terms for a decrease in velocity are
Which statement is true about the law of conservation of energy for an object released from a certain height above the ground
The question is really specific enough, but I will take a guess. If nothing else changes (like the mass or the gravitational constant) then the Potential Energy will increase with an increase in height. Ep will decrease with a decrease in height.
If you are talking about Ke, then the height does not matter unless the object is moving up. Then it slows down. When that happens the Ke decreases because the formula for Ke = 1/2 m v^2. If v becomes less then Ke becomes less.
I suppose you could say if the object is going down and the distance is decreasing then the speed will increase. It's an inverse relationship.
I think you are best talking about Pe.
Two forces of 10 N and 30 N are applied to a 10 kg box. Find (1) the box’s acceleration when both forces point due east and (2) the box’s acceleration when 10 N force points due east and 30 N force points due west.
4 m/s²
Explanation;When both forces point due east then;
the resultant force will be; 10 + 30 = 40 N due east
But; From second Newton's law of motion;
F = ma
Thus;
a = F/m ; F= 40 N and mass = 10 kg
= 40/ 10
= 4 m/s² to wards east
2. Answer;1 m/s²
Explanation;when 10 N force points due east and 30 N force points due west then;
the resultant force will be; 30 N - 10 N = 10 N due west
But; From second Newton's law of motion;
F = ma
Thus;
a = F/m
= 10 /10
= 1 m/s² , towards the west direction
Explanation:
Given that,
First force = 10 N
Second force = 30 N
Mass of box = 10 kg
(1). When both forces point due east
Then the net force will be
[tex]F_{net}=F_{1}+F_{2}[/tex]
[tex]F_{net}=10+30[/tex]
[tex]F=40 N[/tex]
We need to calculate the acceleration
Using newton's second law
[tex]F= ma[/tex]
put the value into the formula
[tex]40=10\times a[/tex]
[tex]a=\dfrac{40}{10}[/tex]
[tex]a=4\ m/s^2[/tex]
The box accelerate towards east.
(2). When 10 N force points due east and 30 N force points due west.
Then the net force will be
[tex]F_{net}=F_{2}-f_{1}[/tex]
[tex]F_{net}=30-10=20\ N[/tex]
We need to calculate the acceleration
Using newton's second law
[tex]F= ma[/tex]
[tex]20=10\times a[/tex]
[tex]a=\dfrac{20}{10}[/tex]
[tex]a=2\ m/s^2[/tex]
The box accelerate towards west.
Hence, This is the required solution.
Which describes how to compare the energy of two different waves?
A. measure their frequencies
B. measure their periods
C. measure their amplitudes
D. measure their wavelengths
C. measure their amplitudes
Explanation;The amount of energy in a wave is related to its amplitude and its frequency.The amplitude of a wave is how the wave is measured from the rest position or mid-line to the top of a crest or bottom of a trough, measured in meters.A high amplitude wave is a high-energy wave, and a low-amplitude wave is a low-energy wave. For instance in the case of sound waves, a high amplitude sound will be loud, and a low amplitude sound will be quiet.C measures their amplitudes. Hope this helps! :)
Help 10 points!
Digesting a banana before running a race is an example of converting
nuclear energy into mechanical energy.
nuclear energy into mechanical energy as well as heat.
chemical energy into mechanical energy.
chemical energy into mechanical energy as well as heat.
chemical energy into mechanical energy as well as heat.
Answer:
Explanation:
A washing machine is plugged into a wall outlet that has voltage of 240 volts. The total resistance present in the machine's wiring is 12 ohms. What current runs through this current
The resistance between the two sides of an outlet should be infinite. The two sides of the outlet are not connected to one another in any fashion as they are two sides of a circuit. The diagram below shows how this works. In an AC circuit, as shown below, the black wire provides AC power, the white is common, and the green is ground. Back in your breaker box, the common wires all go to one buss bar that is to earth ground and the ground wires go to earth ground as well by a separate path making sure that the residual voltage on the common doesn't cross over to the ground wire of another circuit. In the right hand diagram, they show how to connect wires for a series (daisy chain) to another outlet.
So my question is why are you trying to measure resistance here? Normally we would measure voltage. Are you trying to diagnose a circuit problem? In a 110vac system you should have 110vac from black to white and black to green and none from white to green (ideally if nothing is plugged into any outlets). With the breaker off, you should be able to measure the resistance between the two posts on the black side, and that should be 0ohms as they are the same point.
Current = (voltage) / (resistance)
Current = (240 V) / (12 ohms)
Current = 20 Amperes
A brick lands 10.1 m from the base of a building. If it was given an initial velocity of 8.6 m/s [61º above the horizontal], how tall is the building?
First, we have to establish the reference system. Let's assume that the building is on the negative y-axis and that the brick was thrown at the origin (see figure attached).
According to this, the initial velocity [tex]V_{o}[/tex] has two components, because the brick was thrown at an angle [tex]\alpha=61\º[/tex]:
[tex]V_{ox}=V_{o}cos\alpha[/tex] (1)
[tex]V_{ox}=8.6\frac{m}{s}cos(61\º)=4.169\frac{m}{s}[/tex] (2)
[tex]V_{oy}=V_{o}sin\alpha[/tex] (3)
[tex]V_{oy}=8.6\frac{m}{s}sin(61\º)=7.521\frac{m}{s}[/tex] (4)
As this is a projectile motion, we have two principal equations related:
In the x-axis:[tex]X=V_{ox}.t[/tex] (5)
Where:
[tex]X=10.1m[/tex] is the distance where the brick landed
[tex]t[/tex] is the time in seconds
If we already know [tex]X [/tex] and [tex]V_{ox}[/tex], we have to find the time (we will need it for the following equation):
[tex]t= \frac{X}{ V_{ox}}[/tex] (6)
[tex]t=2.42s[/tex] (7)
In the y-axis:[tex]-y=V_{oy}.t+\frac{1}{2}g.t^{2}[/tex] (8)
Where:
[tex]y[/tex] is the height of the building (in this case it has a negative sign because of the reference system we chose)
[tex]g=-9.8\frac{m}{s^{2}}[/tex] is the acceleration due gravity
Substituting the known values, including the time we found on equation (7) in equation (8), we will find the height of the building:
[tex]-y=(7.521\frac{m}{s})(2.42s)+\frac{1}{2}(-9.8\frac{m}{s^{2}}).(2.42s)^{2}[/tex] (9)
[tex]-y=-10.52m[/tex] (10)
Multiplying by -1 each side of the equation:
[tex]y=10.52m[/tex] >>>>This is the height of the building
A spacecraft is launched from Earth toward the moon where will the spacecraft be when the gravitational forces acting on it are equal
A closer to earth than to the moon because the moon has greater mass than the earth
B closer to the moon because the moon greater mass than the earth
C closer to earth than to the moon because earth has greater mass
D Closer to moon than earth because earth has a greater mass than the moon
Answer:
D Closer to moon than earth because earth has a greater mass than the moon
Explanation:
As we know that gravitational force is given by
[tex]F = \frac{Gm_1m_2}{r^2}[/tex]
so here if the net gravitational force at some distance between moon and earth is zero or equal due to moon and earth then in that case
[tex]F_{moon} = F_{earth}[/tex]
so here we can say
[tex]\frac{GM_m m}{r_1^2} = \frac{GM_e m}{r_2^2}[/tex]
so here we will have
[tex]\frac{M_m}{M_e} = \frac{r_1^2}{r_2^2}[/tex]
since mass of earth is more than mass of moon so we can say
[tex]\frac{r_1}{r_2} < 1[/tex]
so here we have
[tex]r_1 < r_2[/tex]
so the position is closer to moon because moon is of smaller mass than earth
Final answer:
In a spacecraft launched from Earth toward the moon, the spacecraft will be closer to the moon than to Earth when the gravitational forces acting on it are equal.
Explanation:
In a spacecraft launched from Earth toward the moon, the spacecraft will be closer to the moon than to Earth when the gravitational forces acting on it are equal.
The gravitational force between two objects depends on their masses and the distance between them. Although the moon has smaller mass compared to Earth, it is much closer to the spacecraft when it reaches that point where the gravitational forces are equal. This is because the spacecraft has traveled a greater distance away from Earth.
So, the correct answer is option B, closer to the moon because the moon has greater mass than the earth.
How do informal and formal learning differ? One is more structured than the other. One requires less effort. One has less significance than the other. One is the best way to learn.
Informal and formal learning both require effort and are significance. Neither is better than the other. So the answer is "One is more structured than the other."
What happens to the charge lost by an object?
They become charged particles called ions.
a hot metal bolt of mass 0.05 kg and specific heat capacity 889 joules per kg degree celsius is dropped into a calorimeter containing 0.15 kg water at 21 degrees celsius. the bolt and water resch a final temperature of 25 degrees celsius. what is the initial temperature of the bolt? the specific heat capacity of water is 4186 joules per kilogram degrees celsius.
80.87 °C
Explanation;Change in Temp of metal = (C of water *mass of water* Change in temp of water)/(C of metal*mass of metal)
That is;
Change of temp. of metal
= [(4186 J/kg*°C)×(0.15kg)×(25°C-21°C)/[(899 j/kg*C)×(0.050kg)
= 55.87 °C
The change in temp of the metal is -55.87 °C as the metal cools down
Therefore;
Change in temperature = Final Temperature-Initial Temperature Initial Temperature = Final Temp.-Change in Temp
=25 °C- (-55.87 °C)
= 80.87 °C
A projectile is shot from the edge of a cliff 125 m above ground level with an initial speed of 65.0 m/s at an angle of 37º above the horizontal. Determine the the magnitude and the direction of the velocity at the maximum height.
Answer:
51.9 m/s, horizontal
Explanation:
The horizontal and vertical components of the initial velocity of the projectile are given by:
[tex]v_x = v cos \theta=(65.0 m/s)(cos 37^{\circ})=51.9 m/s\\v_y = v sin \theta=(65.0 m/s)(sin 37^{\circ})=39.1 m/s[/tex]
In a projectile motion, the horizontal component of the velocity does not change (because there are no forces acting in the horizontal direction), while the vertical velocity changes according to:
[tex]v_y(t)=v_{0y}-gt[/tex]
where g=9.8 m/s^2 is the acceleration due to gravity. However, at the point of maximum height, the vertical velocity is zero (because it is the point at which the projectile starts falling down), so the magnitude of the resultant velocity will simply be equal to the horizontal component:
v = 51.9 m/s
and the direction will be horizontal.
The magnitude of the velocity at the maximum height is 52.0 m/s and the direction is horizontal.
Explanation:To determine the magnitude and direction of the velocity at the maximum height of a projectile, we need to analyze its motion. At the maximum height, the vertical component of the velocity becomes zero, while the horizontal component remains constant. Since the initial velocity is given as 65.0 m/s at an angle of 37º above the horizontal, we can use trigonometry to determine the horizontal and vertical components of the velocity.
The horizontal component of the initial velocity can be calculated as: Vx = initial velocity * cos(angle) = 65.0 m/s * cos(37º) = 52.0 m/s
At the maximum height, the vertical component of the velocity is zero. We can calculate the vertical component of the initial velocity as: Vy = initial velocity * sin(angle) = 65.0 m/s * sin(37º) = 39.0 m/s
Therefore, at the maximum height, the magnitude of the velocity is 52.0 m/s and the direction is horizontal or along the x-axis.
50 ml of milk at 5°C is added to 200 ml of hot chocolate at 95°C. What do you think the approximate new temperature is?
76.3°C
Explanation;Considering the fact that;
Specific heat capacity of the hot chocolate = 3.751 kJ/kg C°
Specific heat capacity of milk is 3.93 kJ/(kg.C°)
But;
Heat gained by milk = Heat lost by hot chocolate
If the final temperature is x , then
Heat gained by milk
= 0.05 × 3.93 × (x-5)
= 0.1965x - 0.9825
Heat lost by hot chocolate;
= 0.2 × 3.751 × (95-x)
= 71.269 - 0.7502x
Therefore;
0.1965x - 0.9825 = 71.269 - 0.7502x
0.1965 x + 0.7502x = 71.269 + 0.9825
0.9467 x = 72.2515
x = 76.319 °C
Approximately, the new temperature is 76.3°C
two wires a and b have equal lengths and are made of same material. If the diameter of wire A is twice that of wire B, which has the greater extension for a given load?
Answer:
It should be A.
Explanation:
Wire A and wire B are made from the same material and have the same length, however, wire A is wider which would allow more electricity or power to be transformed.
Unless im understanding your question wrong, but from what I do understand it is most likely A.
Hope this helps, could you mark me brainliest if it is right?
PLZ HELP ME FAST! How is frequency related to energy? Graph the relationship between the frequency and energy of a radio wave vs other types of electromagnetic waves on the graph below. Write 1- 2 sentences explaining the relationship you drew.
Do Not Know but let me ask my Brother bc he did it last Year
In which situation is the gravitational force between two objects hard to detect? (Options)
a. If the mass of each object is very small.
b. If the objects are very close together.
c. If the mass of one of the objects is very great.
d. If the mass of both objects is very great.
Answer:
Hence, the correct option is (A) "If the mass of each object is very small".
Explanation:
The gravitational force between two objects is directly proportional to the product of masses and inversely proportional to the square of the distance between them.
The mathematical expression is given by :
[tex]F=G\dfrac{m_1m_2}{d^2}[/tex]
d is the distance between masses
Gravitational force is one of the fundamental force in the universe. If the masses of objects is too small, then their interaction with each other is hard to detect.
Hence, the correct option is (A) "If the mass of each object is very small".