Answer:
The stopping car has negative acceleration.
Explanation:
We know acceleration is the rate of change of velocity. That is
Acceleration(a) = ( Final velocity - Initial velocity )/ Time taken.
Here Final velocity = 0 km/h( car stops) and initial velocity = 30 km/h
So acceleration = (0-30)/time = -30/ time
Time is always positive , so -30/time is negative, so the stopping car has negative acceleration.
A person is trying to lift a crate that has a mass of 30 kg. The normal force of the floor is currently supplying 150 N of force. How much force is the person currently exerting?
144
150
294
294
The person is exerting an equal force of 150 N against the crate, as per Newton's Third Law of Motion, meaning the force exerted by the person is equal to the normal force of 150 N.
Explanation:To determine how much force a person is currently exerting to lift a crate with a mass of 30 kg, given the normal force supplied by the floor is 150 N, we need to consider the equal and opposite force applied by the person. According to Newton's Third Law of Motion, if the normal force acting upward from the floor is 150 N, then the person must be exerting an equal amount of force in the opposite direction, which would also be 150 N in order to maintain static equilibrium (assuming no other vertical forces are acting on the system, such as acceleration or additional weights).
An area where the particles in a medium are spaced close together is called a _____.
An area where the particles in a medium are spaced close together is called compression.
Answer : Compression
Explanation :
An area where the particles in a medium are spaced close together is called a compression. In this region the particles are very close to each other.
In the attached figure, the rarefaction and compression is shown very clearly. In rarefaction, the particles of medium are very far apart form each other.
The distance between two consecutive compression and rarefaction is called the wavelength of wave.
So, the compression is the area where the particles are close to each other.
What step of the rock cycle happens as the sea stacks are broken down
D. Weathering
The six steps of the rock cycle includes Weathering and Erosion, Transportation, Deposition, Compaction and Cementation. Metamorphism, Rock Melting.
Deposition is the process where rock particles sink at the rivers and become sediment.
Weathering is the process by which wind and water breaks down igneous, sedimentary, and metamorphic rocks. The process refers to large rocks broken down into smaller pieces and the broken off particles stay in the area.
True or false: the energy that is related to moving parts is called electrical energy
False, that would be kinetic energy.
If an object is dropped from a tall building and hits the ground 3.0 s. later, what is the magnitude of the object's displacement in 1.0 s.; in 2.0 s.?
1.0 s. =
m
2.0 s. =
m
Find the velocity of the object after one second.
v = vo + at
v = (0 m/s) + (9.8 m/s^2)(1 s)
v = 9.8 m/s
Now, using that, you can find the displacement in that one second between 1 and 2.
d = vot + (1/2)at^2
d = (9.8 m/s)(1 s) + (1/2)(9.8 m/s^2)(1 s)^2
d = 14.7 m
Answer: In 1.0 s , Displacement = 4.9 m
In 2.0 s, Displacement = 19.6 m
Explanation: Using formula for equation of motion
[tex]h=u\times t + \frac{1}{2}\times g\times t^{^{2}}[/tex]
Initially , u= 0 m/s , t= 1.0 s and g=9.8 [tex]\frac{m}{s^{2}}[/tex]
Therefore [tex]h_1= 0 + \frac{1}{2}\times 9.8\times 1^{2} m = 4.9 m[/tex]
In Case t=2.0 s
[tex]h_2= 0 + \frac{1}{2}\times 9.8\times 2^{2} m = 19.6 m[/tex]
Please help with 3 questions about acceleration
A great, helpful, useful definition of acceleration is
A = (change in speed) / (time for the change) . <== you should memorize this
This simple tool will directly solve all 3 problems.
The REASON for assigning these problems for homework is NOT to find the answers. It's to help YOU find out whether you know this definition, to let you go back and review it if you don't, and to give you a chance to practice using it if you do. Noticed that if you get the answers from somebody else, you lose all of these benefits.
The only wrinkle anywhere here is in #3, because when you use this definition, the unit of time has to be the same in both the numerator and the denominator.
So for #3, you have to EITHER change the km/hr to km/sec, OR change the 4sec to a fraction of an hour, before you plug anything into the definition.
Which of the following must be true about an object for it to be in uniform circular motion? A.It must have zero centripetal acceleration. B, It must have increasing centripetal acceleration. c. It must be moving at a constant speed. D. It must be moving with a constant velocity.
Answer:
It must be moving at a constant speed
Explanation:
When an object move in a circular path, its motion is called uniform circular motion. The object moves with constant speed but the direction always changes. We know that the rate of change of velocity is called acceleration of the object.
In circular motion, the centripetal acceleration act towards the center of circle. The force acting on the object is called centripetal force. It is given by :
[tex]F_c=\dfrac{mv^2}{r}[/tex]
Hence, the statement that is true about an object to be in uniform circular motion is (C) " It must be moving at a constant speed".
The following must be true about an object for it to be in uniform circular motion C. It must be moving at a constant speed.
What happens in uniform circular motionIn uniform circular motion, an object travels in a circular path at a constant speed, but its velocity is not constant because the direction of the velocity is constantly changing.
The centripetal acceleration is directed toward the center of the circle and is responsible for keeping the object in its circular path, but the object's speed remains unchanged.
Read more on uniform circular motion here https://brainly.com/question/30215891
#SPJ4
Why can we never prove that a hypothesis is true?
Scientific hypotheses cannot be proven to be true but can be strongly supported by evidence.
Hypotheses in science cannot be proven to be true with absolute certainty because scientific knowledge is always subject to revision and refinement based on new evidence. However, we can provide strong evidence supporting a hypothesis through experimentation and observation. Scientific theories are formed when a hypothesis has been extensively tested and supported by a large body of evidence. Such theories serve as the most accurate explanations for natural phenomena and are considered to be highly reliable.
Learn more about Hypotheses in Science here:https://brainly.com/question/33813660
#SPJ6
What is another hypthesis that might expain hy hummingbirds seem to prefer red flowers
Because it's maybe the only color they see.
An archer wants to hit a target that is dropped from a tower. At the sound of a horn, the archer is to shoot an arrow; at the same instant, the target will be dropped. Ignoring air resistance, where should the archer aim in order to hit the target?
A. slightly above the initial position of the object
B. at the spot where the archer hopes to hit the target
C. directly at the initial position of the object
D. above the spot where the archer hopes to hit the target
It has to be D because the arrow will drop as it moves, if it were a gun, you'd lead the target so fire below it, but due to it being an arrow, you aim high not low. Also, they didnt specify how fast anything is, so you'd probably miss if you actually did it.
Answer:
C. directly at the initial position of the object
Explanation:
As we know that archer wants to hit the target at a given position but at the same time when archer shot the arrow the the target is also dropped under gravity
So here the arrow will move simultaneously in two directions
a) horizontal motion with uniform speed
b) motion under gravity
so here the arrow will move under gravity and drops the same distance in same time as that the target will drop due to gravity
so here the motion of arrow will hit the target if the archer initial shot at the initial position of the target
At a distance of 0.75 meters from its center, a Van der Graff generator interacts as if it were a point charge, with that charge concentrated at its center. A test charge at that distance experiences an electric field of 4.5 × 105 newtons/coulomb. What is the magnitude of charge on this Van der Graff generator?
Since the Van de Graaff generator is given to behave like a point charge, we can use the equation for Electric Field, given as
[tex]E = \frac{kQ}{r^{2} }[/tex]
where, [tex]k = \frac{1}{4\pi ε₀}[/tex] = [tex]8.99 X 10^{9} \frac{Nm^{2} }{C^{2} }[/tex]
r is the distance between the generator and the test charge = 0.75 m
E is the magnitude of the Electric Field Strength = [tex]4.5 X 10^{5} N/C[/tex]
Rearranging the equation, making Q the subject of the formula, we have
[tex]Q = \frac{E.r^{2} }{k}[/tex]
Plugging in the numerical values and simplifying them gets us
[tex]Q = 0.2815 X 10^{-4} \\[/tex]
Thus, the charge on the Van de Graaff generator is 28.16 μC.
Answer:
Answer is 2.8 × 10-7 coulombs.
Describe the difference between continuous reinforcement and intermittent reinforcement.
(psychology)
A continued schedule of reinforcement (CRF) happens when reinforcement is delivered after each and ever single targeted behavior
While a intermittented schedule of reinforcement (INT) is when reinforcement is delivered after only a few behaviors or responses not after each and every single one
Continuous reinforcement and intermittent reinforcement differ as follows:
In continuous reinforcement, each and every emission of the target behavior always receives reinforcement.
That is, each time the desired or studied behavior is carried out, it will result in the arrival of the reinforcer.
In the case of intermittent or partial reinforcement, only some of the times that the behavior is carried out is a reinforcer received, so that not every time we do the behavior we will get a reward.
Therefore, we can conclude that in intermittent reinforcement the behavior of the person is only reinforced on certain occasions and in continuous reinforcement the person is constantly rewarded for an action or behavior.
Learn more about reinforcement here: https://brainly.com/question/5162646
two objects each weighing 2kg are lifted through the same distance in 4s and 1s respectively. which scenario requires more work?
i believe it would be the same because time doesn't matter when calculating total work done.
Work=FxD
F=force
D=distance
Final answer:
The scenario that requires more work is when the force applied is greater.
Explanation:
Work is defined as the product of force and displacement.
The work done on an object is given by the formula: work = force × distance × cosine(θ), where θ is the angle between the force and displacement vectors.
In this case, both objects are lifted through the same distance. Therefore, the work done on each object is equal to the force applied to lift the object multiplied by the distance lifted.
The time taken to lift the object does not affect the work done.
So, the scenario that requires more work is when the force applied is greater.
If an object is said to be moving at 10m/s due north. The measurement 10 m/s would be best described as
The answer is velocity
Answer: Speed.
Explanation :
It is given that if an object is said to be moving at 10 m/s due north. In this case, the velocity of an object is given. It has both magnitude and direction as well.
Velocity is a vector quantity. 10 m/s is the magnitude of velocity and it is moving towards the north direction.
We know that the sped of an object is the total distance covered divided by the total time is taken. It is a scalar quantity.
So, 10 m/s shows the speed of an object.
Which is a nonrenewable resource for the production of nuclear energy?
A.coal
B.natural gas
C.geothermal
D.uranium
D. Uranium
Hope this helps :)
Answer:
It is Uranium.
Option (D)
Explanation:
Uranium is a radioactive substance.
When uranium is bombarded with neutrons it emits very large amount of energy along with some stable substances. The energy emitted s called nuclear energy.
The reaction is given by
As you sit in front of a computer, which of the following is exerting the greatest gravitational force of attraction on you?
A. Earth
B. Your classmate across the room that you've had your eye on
C. Your computer
D. Your chair
Answer: Earth
Explanation:
The military uses a special instrument to detect this type of wave to help improve night vision.
A. infrared waves
B. gamma rays
C. radio waves
D. ultraviolet rays
Night vision equipment detects infrared radiation. Where it detects some, it paints the corresponding place on a screen with visible rays.
The fact that the sun exerts a force on you, even though it it very far away, is a consequence of the Universal Law of __________.
Gravitation, gravity won't work, it has to be gravitation
the answer is gravitation :D
What is the unit used for measuring both work and energy?
A) joule
B) Newton
C) Pascal
D) meter
A
the unit used for measuring both work and energy is the joule
✿━━━━@♥ℳg━━━━✿
[tex]\boxed{Explained\:Answer}[/tex]
______________________________
✿━━━━@♥ℳg━━━━✿
What is the unit used for measuring both work and energy?
A) joule✔✔
B) Newton
C) Pascal
D) meter
Which reaction would result in a change in odor, indicating a chemical change has occurred?
odour = gas suggesting molecular rearrangement ... chem change
A change in odor can indicate a chemical change has occurred. Examples include the oxidation of iron in myoglobin when cooking red meat and a banana turning brown.
Explanation:A change in odor can indicate a chemical change has occurred. Examples of reactions that result in a change in odor include the oxidation of iron in myoglobin when cooking red meat, which causes a red-to-brown color change and change in smell. Another example is a banana turning brown, where new, darker substances form and the odor changes. These changes in odor are indicators that chemical reactions have taken place.
Learn more about Chemical changes here:https://brainly.com/question/23693316
#SPJ3
Give an example of a scientific hypothesis. Explain how you would test it, and how it could be falsified (proved untrue).
my hypothesis is that If you drop a piece of buttered toast, it will land butter side down.
I tested it by dropping 10 pieces of buttered toast off the table and noted on which side it landed
It could be falsified cause I just made all of this up. In essence, it's like flipping a coin, 50/50 chance so I could say that 5 landed butter up and 5 landed butter down.
A scientific hypothesis, such as 'Plant growth is positively affected by the presence of light', must be testable and falsifiable. It is tested and potentially falsified through controlled experiments, where one group is exposed to the variable under question while the other is not. Science advances by testing and potentially disproving such hypotheses, never claiming absolute proof.
Example of a Scientific Hypothesis and Testing
A scientific hypothesis is a proposed explanation for a phenomenon that is testable and falsifiable. An example of a hypothesis could be: 'Plant growth is positively affected by the presence of light'. To test this hypothesis, you could conduct an experiment with two groups of plants: one group, the experimental group, would be exposed to light, while the control group would not. Plant growth can be measured over a period to determine the effect of light. The hypothesis would be falsified if the plants in darkness grew as well or better than the plants exposed to light.
Falsifiability
Falsifiability is a core principle in science, ensuring that hypotheses can be disproven. A non-falsifiable hypothesis, such as 'Red is a better color than blue', cannot be tested or disproven, and thus is not scientific. Falsifiable hypotheses contribute to the scientific method by ensuring that they can be subject to empirical testing. If ongoing tests and experiments consistently fail to disprove a hypothesis, it gains support as a valid explanation until potentially falsified by future research.
Which is a part of interphase? A. S phase B. Anaphase C. Telophase D. Cytokinesis
The answer choice that is a part of the interphase is A. S phase.
What is Interphase?Interphase is the stage of the cell cycle that prepares the cell for division and is divided into three phases: G1, S, and G2.
During the S phase (synthesis phase), DNA replication occurs, meaning the cell's genetic material is duplicated in preparation for cell division.
Hence, it can be noted that the other answer choices are not a part of interphase as the S phase is the synthesis phase that helps prepare the cell for division
Read more about interphase here:
https://brainly.com/question/28307942
#SPJ1
Final answer:
The part of interphase related to chromosome duplication is the S phase. Interphase, which includes the S phase, is separate from mitotic stages like anaphase and telophase and the cell division process of cytokinesis.
Explanation:
The part of interphase that involves the replication of DNA is known as the S phase. Therefore, the answer is A. S phase. Interphase consists of three main stages in the cell cycle: the G1 phase, S phase (synthesis phase), and G2 phase. During the S phase, the chromosomes are duplicated, ensuring that each new cell will have a complete set of chromosomes after cell division.
Interphase is distinct from the stages of mitosis, which include prophase, metaphase, anaphase, and telophase. Finally, cytokinesis is the process where the cytoplasm divides, forming two separate cells.
In contrast to interphase, anaphase is a stage of mitosis where sister chromatids are separated and pulled to opposite poles of the cell. Telophase is the stage when the chromosomes begin to decondense, and new nuclear envelopes start to form around the daughter nuclei. Cytokinesis, while often occurring concurrently with telophase, is considered a separate process from mitosis and is not part of interphase.
What is the appropriate unit of measurement for pitch?
The appropriate unit of measurement for pitch is mel.
There are several definitions of 'pitch', but I think you mean how 'high' or 'low' a sound sounds to our ear.
If that's it, then you're talking about the frequency of the sound, and the unit is 'vibrations per second' or 'Hertz' (Hz) .
HURRY PZZ 30PTS
Which of the following characteristics differentiates an autotroph from a heterotroph? Question 1 options: An autotroph can only obtain its energy from a heterotroph. An autotroph must obtain its energy from a heterotroph or other autotroph.. Heterotrophs only obtain their energy from the Sun. A heterotroph must obtain its energy from an autotroph or other heterotroph. Autotrophs only obtain their energy from the Sun. A heterotroph can only obtain its energy from an autotroph.
If someone told you they had a career in either ecology, paleontology, or botany, what area of science is this?
Question 2 options:
astronomy
biology
physics
chemistry
Which of the following statements is true for all living things (organisms)?
Question 3 options:
None of The Above
All living things are made up of one or more cells.
All living things have organs.
All living things produce their own food.
How are these related: human, mold, bacteria?
Question 4 options:
They are all protists.
They are all organisms.
They are all Domain Bacteria.
They are all Kingdom Animalia.
What would happen if several salmon in an area were only able to lay 100 eggs instead of what they normally lay?
Question 5 options:
Nothing. The population will most likely stay the same.
The population will most likely die out since most of the eggs are usually eaten and destroyed.
The population will most likely decrease some but the salmon will still survive in the area.
The population will most likely increase dramatically since fewer eggs means better eggs
An organism that has been thriving, has died. Which of the following is NOT a cause of its demise?
Question 6 options:
appropriate enviornment
soil
food
water
The leaves on a green plant soak up sunlight to make food. A cow's stomach digests grass that was eaten. How are these alike?
Question 7 options:
They are both show how organisms continue growth.
They both show how organisms use metabolism.
They are both examples of heredity in organisms.
They are both ways organisms maintain homeostasis.
While exercising, the body releases sweat. Which of the below is a reason this occurs?
Question 8 options:
None of the Above
Homeostasis
Metabolism
Survival of the fittest
Based on the classification system, which subgroup would you find at the bottom?
Question 9 options:
Class
Phylum
Domain
Species
You are taking a walk in the woods. You come upon a butterfly with coloring and other features you have not seen before. You want to find out its scientific name so you can tell your friends and family about it, and they can look it up. It would be best to use what to determine this?
Question 10 options:
Classification system
dichotomus key
Google
science book
Who developed a system of classifying organisms by genus and species?
Question 11 options:
Watson
Mendel
Linnaeus
Darwin
Autrotrophs obtain their energy from the sun
Biology
All living things have. Organs
Answer:
Q1: A heterotroph can obtain its energy by consuming another autotroph or a heterotroph.
Q2: Biology.
Q3: All living things are made up of one or more cells.
Q4: They are all organisms.
Q5: The population will most likely die out since most of the eggs are usually eaten and destroyed.
Q6: Appropriate environment.
Q7: They are both ways organisms maintain homeostasis.
Q8: Homeostasis.
Q9: Species
Q10: Dichotomous key.
Q11: Carolus Linnaeus
Mrs. Newman’s class decides to perform an experiment during a class connect session to determine how long it takes different objects to hit the floor when dropped from the student’s desk. Each student dropped three notebooks, one weighing 0.5 pound, one weighing 1.0 pound, and one weighing 2.5 pounds. What would you predict about the times it took for each of them to hit the floor?
a) The 0.5lb notebook would hit the floor first
b) The 0.5lb notebook would hit the floor last
c) The 2.5lb notebook would hit the floor first
d) All notebooks would fall at the same time
e) All notebooks would remain suspended in the air
D, all notebooks would hit the floor at the same time. The time it takes to hit the floor is independent of their weight, but rather dependent on the acceleration of gravity. Since gravity is constant, they will all hit the floor at the same time.
the correct answer would be D because they all have the same gravitational pull
If a rock climber accidentally drops a 77.5-g piton from a height of 215 meters, what would its speed be just before striking the ground? ignore the effects of air resistance.
Let us list out what we know from the question.
Initial Velocity [tex]V_{i} = 0[/tex] since the piton is 'dropped'.
Vertical Displacement of the piton D = 215 m
Acceleration due to gravity [tex]a = 9.8 m/s^{2}[/tex]
Final Velocity [tex]V_{f} = ?[/tex]
Using the equation, [tex]V^{2} _{f} = V^{2} _{i} + 2aD[/tex] and plugging in the known values, we get
[tex]V^{2} _{f} = 0^{2} + 2(9.8)(215)[/tex]
Simplifying by taking square-root on both sides gives us [tex]V_{f} = 64.915 m/s[/tex]
Thus, the speed of the piton just before striking the ground is 65 m/s.
The speed of the piton just before striking the ground would be approximately 64.94 meters per second.
To determine the speed of the piton just before it strikes the ground, we can use the kinematic equation for an object in free fall under the influence of gravity, ignoring air resistance. The equation is:
[tex]\[ v = \sqrt{2gh} \][/tex]
Given:
- The mass of the piton (m) is [tex]\( 77.5 \, g \)[/tex] or [tex]\( 0.0775 \, kg \)[/tex] (since [tex]\( 1 \, g = 0.001 \, kg \))[/tex],
- The height (h) is 215 m.
We can plug these values into the equation:
[tex]\[ v = \sqrt{2 \times 9.81 \, m/s^2 \times 215 \, m} \] \[ v = \sqrt{2 \times 9.81 \times 215} \] \[ v = \sqrt{4217.7} \] \[ v \approx 64.94 \, m/s \][/tex]
Suppose the mower is moving at 1.5 m/s when the force F is removed. How far (in m) will the mower go before stopping? The frictional force is a constant 26 N and mass of mower is 22kg
The mower will go approximately 1.163 meters before stopping.
Explanation:To determine the distance the mower will go before stopping, we need to calculate the deceleration first. We can use Newton's second law of motion: F = ma. The net external force (F) is the force exerted by the person minus the frictional force, which is 51 N - 24 N = 27 N. The mass of the mower (m) is 22 kg. Rearranging the formula, we get: a = F/m = 27 N / 22 kg = 1.227 m/s².
Then, using the equation v² = u² + 2as, where v is the final velocity (0 m/s when the mower stops), u is the initial velocity (1.5 m/s), a is the deceleration (-1.227 m/s²), and s is the distance we're trying to find. Rearranging the equation, we get: s = (v² - u²) / (2a) = (0 - (1.5)²) / (2 * (-1.227)) = 1.163 m.
Learn more about Stopping distance of a mower here:https://brainly.com/question/29800167
#SPJ3
The lawn mower will travel approximately 0.955 meters before stopping.
To find out how far the lawn mower will travel before stopping, we need to use the principles of physics, specifically the concepts of friction and linear motion. Here’s the step-by-step method:
We start with the given data: The frictional force F opposing the mower’s motion is 26 N, the mass m of the mower is 22 kg, and its initial velocity v0 is 1.5 m/s.The frictional force is the only force acting in the horizontal direction once the pushing force is removed, causing the mower to decelerate.The acceleration a can be found using Newton's second law: a = F/m. Thus, a = 26 N / 22 kg ≈ 1.18 m/s².This acceleration is negative because it is a deceleration (the mower is slowing down): a = -1.18 m/s².To find the stopping distance, we use the kinematic equation: vf² = v0² + 2ad, where vf is the final velocity (0 m/s), v0 is the initial velocity, a is the acceleration, and d is the distance.Rearranging for d: d = (vf² - v0²) / (2a). Plugging in the values: d = (0 - (1.5)²) / (2 * -1.18) ≈ 0.955 m.Therefore, the lawn mower will travel approximately 0.955 meters before coming to a stop.
A gas with constant temperature has a pressure of 4 atm this pressure changes to 0.2 atm causing the volume to increase to 500L what was the initial volume of the gas
Answer:
[tex]25L[/tex]
Explanation:
The problem can be solved using Boyle's law for the volume and pressure of a gas at constant temperature:
[tex]P_{1}V_{1}=P_{2}V_{2}[/tex]
Where the quantities with sub-index 1 are the initial conditions for the gas and the quantities with sub-index 2 are for the final conditions of the gas.
We want to know the initial volume, this is:
[tex]V_{1}=\frac{P_{2}V_{2}}{P_{1}}[/tex]
we also know from the problem that
[tex]P_{1}=4atm\\P_{2}=0.2atm\\V_{2}=500L[/tex]
Thus, the initial volume V1 is:
[tex]V_{1}=\frac{0.2atm*500L}{4atm}[/tex]
[tex]V_{1}=25L[/tex]
Overall, what is the least useful mineral identification property listed here?
A. Streak
B. Hardness
C. Magnetism
D. Specific gravity
C. Magnetism
Very few minerals are magnetic, while streak hardness and specific gravity can be used to identify lots of minerals
A 3kg box is pulled along the floor with a force of P=20 N at an angle of 30 degrees. If the box is moving at a constant velocity, calculate the force of friction f, the normal force N and the weight W.
If force is applied at 30 degree with the horizontal
then first we will find the components of force in two directions
[tex]F_x = 20 cos20[/tex]
[tex]F_y = 20 sin30[/tex]
now we can find normal force by balancing the forces in Y direction
[tex]F_n + Fy = mg[/tex]
[tex]F_n + 20 sin30 = 3*10[/tex]
[tex]F_n + 10 = 30[/tex]
[tex]F_n = 20 N[/tex]
now since block is moving with constant speed
so here forces along horizontal plane will be balanced also
[tex]F_x = F_f[/tex]
[tex]F_f = 20 cos30[/tex]
[tex]F_f = 17.3 N[/tex]
Now the weight of the box is defined as
[tex]W = mg[/tex]
now plug in all values
[tex]W = 3*10 = 30 N[/tex]