Recall that the momentum is given by
[tex]p=m\cdot v[/tex]Where m is the mass and v is the velocity.
[tex]p=2\cdot8=16\;\;\frac{kg\cdot m}{s}[/tex]So, the momentum of the object is 16 kg m/s.
Now, we need to equate this momentum to find the velocity of the other object.
[tex]\begin{gathered} p=m\cdot v \\ 16=10\cdot v \\ v=\frac{16}{10} \\ v=1.6\;\frac{m}{s} \end{gathered}[/tex]Therefore, the object must be traveling at 1.6 m/s to have the same momentum as the other object.
projectile motion lab work i need report
The Projectile Motion Lab is focused on a different type of projectile motion - that of a non-horizontally launched projectile.
What is Projectile Motion LabThe goal of this experiment is to accurately estimate and measure the range and time-of-flight of an angled projectile. Finding the ball's initial speed (muzzle velocity) is necessary before estimating the projectile's range when it is fired off a table at an angle other than horizontal. The projectile motion highlights the important fact that even constant acceleration, which is essentially unidirectional, can produce two-dimensional motion. The primary cause is that the object's initial velocity and force are not in the same direction.To learn more about Projectile Motion Lab refer :
https://brainly.com/question/28884468
#SPJ13
In a classroom, who is a receiver of messages?
The Moon has a mass of 7.35 × 1022 kg and a radius of 1.74 × 106 m. It orbits around the Earth at a distance of 3.84 × 108 m, completing a full rotation every 27.3 days. It also spins on its axis at a speed such that the same side of the moon is always facing the Earth. calculate the angular momentum of the moon in its orbit around the earth, b,calculate the angular momentum of the moon in its rotation around its axis, c,how many times larger is the angular momentum than the rotational angular momentum for the moon?
Givens.
• Mass of the Moon = 7.35x10^22 kg.
,• The radius of the orbit = 3.84x10^8 m.
First, find the tangential velocity.
[tex]v=\frac{2\pi r}{T}=\frac{2\pi\cdot3.84\times10^8m}{2.36\times10^6s}=1022.35\cdot\frac{m}{s}[/tex]Observe that we use the period in seconds, not in days. The transformation we performed is
[tex]T=27.3\text{days}\cdot\frac{86400\sec}{1day}=2.36\times10^6\sec [/tex]Once we have the tangential velocity, we can find the angular momentum of the Moon around the Earth.
[tex]\begin{gathered} L=mvr=7.35\times10^{22}\operatorname{kg}\cdot1022.35\cdot\frac{m}{s}\cdot3.84\times10^8m \\ L=2.9\times10^{34}\operatorname{kg}\cdot\frac{m^2}{s} \end{gathered}[/tex]Therefore, the angular momentum around the Earth is 2.9x10^34.
The angular momentum of the moon can be found using the following formula.
[tex]L=I\cdot w[/tex]Where I is the moment of inertia of the moon and w is the angular velocity.
The moment of inertia of a spherical solid is
[tex]I=\frac{2}{5}mr^2[/tex]The mass of the moon is 7.35 × 10^22 kg and its radius is 1.74 × 10^6 m. So, the inertia is
[tex]\begin{gathered} I=\frac{2}{5}\cdot7.35\times10^{22}\operatorname{kg}\cdot(1.74\times10^6m)^2 \\ I=8.9\times10^{34}\operatorname{kg}\cdot m^2 \end{gathered}[/tex]Using its angular velocity of 2.7x10^-6 rad/s, we find its angular momentum.
[tex]\begin{gathered} L=2.7\times10^{-6}rad/s\cdot8.9\times10^{34}\operatorname{kg}\cdot m^2 \\ L=2.4\times10^{29}\operatorname{kg}\cdot\frac{m^2}{s^{}} \end{gathered}[/tex]The angular momentum of the moon onto itself is 2.4x10^29.
At last, divide both momentums to compare them.
[tex]\frac{L_{\text{earth}}}{L_{\text{moon}}}=\frac{2.9\times10^{34}\operatorname{kg}\cdot\frac{m^2}{s}}{2.4\times10^{29}\operatorname{kg}\cdot\frac{m^2}{s^{}}}=1.2\times10^5[/tex]Therefore, the angular momentum around the Earth is 1.2x10^5 times greater than the angular momentum of the Moon onto itself.
in which ecosystem would a lion hunt a zebra? freshwater
savanna
desert
Answer:
Savanna
Explanation:
lions are in Africa right? Hot deserty climat so the answer would be Savanna.
Answer:
Savanna
Explanation:
Lions are predators in African savanna. They hunt on large herbivore populations of buffalos, impalas, zebras, and even elephants and giraffes.
The amount of potential energy possessed by an object elevated is equal toThe power used to lift itThe work done in liftingThe distance liftedForce needed to lift it
To find:
The amount of potential energy possessed by an object is equal to which of the given quantities?
Explanation:
The potential energy of an object is the energy possessed by the object due to its position.
To lift an object to a certain height, a certain amount of work needs to be done. This work done on the object to lift it will be stored in the object as theopotential energy.
Final answer:
Thus the correct answer is option B, 'the work done in lifting.'
A 100 watt lamp has a resistance of 120 Ω. Find the current in the lamp.Group of answer choices2.15 A1.20 A0.913 A0.833 A
0.913 A
Explanation
the poweris given by
[tex]P=I^2R[/tex]so
Step 1
Let
[tex]\begin{gathered} I=I \\ P=100\text{ watts} \\ \text{resistance}=120\text{ ohm} \end{gathered}[/tex]b) now replace
[tex]\begin{gathered} P=I^2R \\ 100=I^2\cdot120 \\ \text{divide boths sides by 120} \\ \frac{100}{120}=\frac{I^2\cdot120}{120} \\ 0.8333=I^2 \\ \text{square root in both sides} \\ \sqrt{0.8333}=\sqrt{I^2} \\ 0.91287=I \\ \text{rounded} \\ I=0.913\text{ Amperes} \end{gathered}[/tex]therefore, the answeris
0.913 A
I hope this helps you
Electric potential differences are measured in amperes.Question 19 options:TrueFalse
The change in potential energy between two positions when work is done on a charge is called the electric potential difference.
Electric potential difference is measured in joules per coulomb or volt.
Whereas ampere is the unit of current.
Therefore, we can conclude that the given statement is false.
A light wave has a frequency of 6 x 10^8. What is the wavelength of the light wave? (Assume the speed of light to be 3 x 10^8.)
ANSWER
[tex]\begin{equation*} 0.5\text{ }m \end{equation*}[/tex]EXPLANATION
Parameters given:
Frequency of light wave, f = 6 * 10⁸ Hz
Speed of light, c = 3 * 10⁸ m/s
To find the wavelength of the light wave, apply the relationship between speed of light and wavelength:
[tex]\begin{gathered} c=\lambda f \\ \lambda=\frac{c}{f} \end{gathered}[/tex]Hence, the wavelength of the light wave is:
[tex]\begin{gathered} \lambda=\frac{3*10^8}{6*10^8} \\ \lambda=0.5\text{ }m \end{gathered}[/tex]That is the answer.
The main characteristics used to classify stars include all of the following EXCEPT:A. shape.B. brightnessC. colorD. temperature
From the given list of choices, let's select the characteristic that cannot be used to classify stars.
Stars can be said to be self-luminous bodies of gas which shines by radiation gotten from its internal energy sources.
Stars can be classified using five properties:
0. Color
,1. Temperature
,2. Size
,3. Composition
,4. Nature of brightness
Therefore, the characteristic that cannot be used to classify a star is its shape.
All stars look spherical due to their gravitational properties.
ANSWER:
A. Shape
Converting the number0.700 to Scientific Notation7.00 x 10-17.00 x 101O 7x 1010 7x10-1
Explanation
Step 1
Place a decimal by counting the steps to the left until the coefficient of the number is between 1 and 9.
so
[tex]0.700\rightarrow move\text{ the decimal place 1 position 7.000}[/tex]Step 2
Count the number of steps moved. This will be the power of the base 10.
Moving the decimal point to the right gives a negative exponent, whereas moving the decimal point to the left makes a positive exponent.
1 place to the rigth so the exponent is -1
Step 3
In this case, the coefficient is 7 and the 1 steps are moved
so, Multiply the coeeffcient by 10 exp(1), the (1) we got from the previous step
so, the number is scientific notation is
[tex]\begin{gathered} 0.700\rightarrow7\cdot10^{-1} \\ 7\cdot10^{-1} \end{gathered}[/tex]I hope this helps you
Q5. Unless you push a pendulum at the start of it's swing (doing work to give it extra energy), will it ever swing higher than it's starting point? Explain your answer in terms of kinetic and potential energy.
Unless you push a pendulum at the start of it's swing (doing work to give it extra energy), it will never swing higher than it's starting point.
In a pendulum, the total energy of the system always remains constant.
Total energy = Potential Energy + Kinetic Energy
When a bob of a pendulum is raised to hang in the string it gains potential energy because work is done to raise the bob. In a pendulum motion, at the starting point potential energy is at its maximum, meaning kinetic energy is zero.
As it starts to swing the potential energy is converted into kinetic energy. So potential energy decreases and kinetic energy increases. At the lowest point of the swing the kinetic energy is maximum and potential energy is zero. As the motion continues when it reaches the top most point potential energy will be maximum and Kinetic energy will be zero again. Throughout the entire motion total energy remains constant. Only when you push it initially, it will gain extra energy to go higher than the starting point.
Therefore, unless you push a pendulum at the start of it's swing (doing work to give it extra energy), it will never swing higher than it's starting point.
To know more about pendulum
https://brainly.com/question/13764813
#SPJ1
A position versus time graph is shown below.
A Position versus Time graph is shown with y-axis labeled position in meters north up to 20 and x-axis labeled time in seconds up to 10. A line connects points 0, 0 and 1, 4. A horizontal line connects points 1, 4 and 4, 4. A line connects points 4, 4 and 6, 10. A horizontal line connects points 6, 10 and 8, 10. A line connects 8, 10 and 9, 14, and then 10, 15.
Use the graph to determine the instantaneous velocity in m/s of the object at 7 seconds.
0 m/s north
1.4 m/s north
7 m/s north
10 m/s north
A Position versus Time graph is shown with y-axis labeled position in meters north up to 20 and x-axis labeled time in seconds up to 10. The instantaneous velocity in m/s of the object at 7 seconds is 0 m/s north.
What is instantaneous velocity?
Instantaneous velocity, often known as the time derivative of position, is the rate of change (slope) of the position function.
[tex]v=\dot{s}=\frac{ds}{dt}[/tex]
The limit of the average velocity as time approaches 0, or the derivative of x with respect to t, is the instantaneous velocity of an object.
A Position versus Time graph is shown with y-axis labeled position in meters north up to 20 and x-axis labeled time in seconds up to 10. A line connects points 0, 0 and 1, 4. A horizontal line connects points 1, 4 and 4, 4. A line connects points 4, 4 and 6, 10. A horizontal line connects points 6, 10 and 8, 10. A line connects 8, 10 and 9, 14, and then 10, 15.
Use the graph we determine the instantaneous velocity in m/s of the object at 7 seconds is 0 m/s .
To learn more about velocity refer to the link:
brainly.com/question/18084516
#SPJ1
Answer:
the answer is 7m/s north
Explanation:
I took the quiz
calculate the pressure exterted by liquid having a density of 13600 kg/m3 and a depth of 12 meter.
The density of the liquid is,
[tex]d=13600kg/m^3[/tex]The depth is,
[tex]h=12\text{ m}[/tex]The pressure at any depth for a liquid is given by,
[tex]P=\text{hdg}[/tex]Substituting the values we get,
[tex]\begin{gathered} P=12\times13600\times9.8 \\ =1.599\times10^6N/m^2 \end{gathered}[/tex]The required pressure at that depth is,
[tex]1.599\times10^6N/m^2[/tex]Find the acceleration of a toy place whose velocity as a function of time is given by the graph belowat a) t = 4.00 s b) t = 9.00 s and c) t = 11.0 s.
ANSWER:
a) 1 m/s^2
b) -4 m/s^2
c) 0 m/s^2
STEP-BY-STEP EXPLANATION:
The acceleration is given by the following equation:
[tex]a=\frac{\Delta v}{\Delta t}=\frac{v_f-v_i}{t_f-t_i}[/tex]Therefore:
a) t = 4 s
[tex]a=\frac{3-(-3)}{6}=\frac{3+3}{6}=\frac{6}{6}=1[/tex]b) t = 9 s
[tex]a=\frac{-5-3}{10-8}=\frac{-8}{2}=-4[/tex]c) t = 11 s
[tex]a=\frac{-5-(-5)}{12-10}=\frac{-5+5}{2}=\frac{0}{2}=0[/tex]Doubling the frequency of a sound wave within a uniform (unchanging) medium will _________. Select all that apply.a- halve the amplitude of the waveb- halve the wavelength of the wavec- double the speed of the waved- halve the speed of the wavee- double the amplitude of the wavef- double the wavelength of the wave
ANSWER:
b- halve the wavelength of the wave
STEP-BY-STEP EXPLANATION:
We have that the speed of a wave is dependent upon the properties of the medium through which the wave is moving. An alteration in the properties of the medium will result in a change in the speed at which the wave moves through that medium.
That is to say that when changing frequency, what changes is the wavelength.
They are inverse, so when the frequency doubles, the wavelength is divided in half.
Therefore, the correct answer is:
b- halve the wavelength of the wave
An airplane flies on a level path. There is a pressure difference of 587 Pa between the lower and upper surfaces of the wings. The area of each wing surface is about 100 m2. The air moves below the wings at a speed of 80.5 m/s. Estimate the weight of the plane.
ANSWER:
117400 N
STEP-BY-STEP EXPLANATION:
Given:
Pressure difference = 587 Pa
Surface area of the wing = 100 m^2
Speed of the sir below the wing = 80.5 m/s
The weight of the plane is the force due to the pressure difference of upper and lower side of both wings. Therefore:
[tex]\begin{gathered} F=\Delta P\cdot2A \\ F=587\cdot2\cdot100 \\ F=117400\text{ N} \end{gathered}[/tex]The weight is a force of 117400 N.
Which of the following most directly limits the number of organisms in a community?
A. Amount of available shelter
B. Wind
C. Hours of daylight/day
D. UV radiation
The following most directly limiting the number of organisms in a community is the amount of available shelter. Option A.
Examples of limiting factors are biological in nature such as competition with other organisms for food mates and resources. Others are abiotic such as space temperature altitude and the amount of sunlight available in the environment. Limiting factors are usually expressed as a lack of a particular resource.
Limiting factors are resources or other factors in the environment that can limit population growth. The limiting factors are the lack of food supplies and the lack of space. Competition for resources such as food and space will stop the rate of increase and the population will plateau. Immigration is the permanent immigration of some individuals coming into an existing population from outside.
Learn more about Limiting factors here:-https://brainly.com/question/3611138
#SPJ1
Question 2 of 25Which of the following is an SI unit of measurement?OA. LiterOB. YardOC. QuartOD. Gallon
Given:
Some units are given
To find:
The unit of measurement
Explanation:
Liter, Quart, and Gallon are the units of measurement of the volume of a fluid.
The Yard is the unit of the measurement of length.
The SI unit of measurement is Liter.
You have an unknown substance with a mass of
40 g and a volume of 100 cm³.
What is its density?
Will it sink or float in water?
A 1200-kg car accelerates from rest to 20.5 m/s in 4.50 s. What is the average power delivered by the engine? Use the work-energy theorem to calculate for the work (in terms of kilojoules [kJ]). Show your complete solutions.
Answer:
Explanation:
Given:
m = 1200 kg
V₀ = 0 m/c
V = 20.5 m/s
t = 4.50 s
____________
N - ?
1)
Car acceleration:
a = (V - V₀) / t = (20.5 - 0) / 4.50 ≈ 4.56 m/s²
2)
Vehicle traction force:
F = m·a = 1200·4.56 ≈ 5 470 N
3)
Vehicle speed:
V = V₀ + a·t = 0 + 4.56·4.50 ≈ 20.5 m/s
4)
Average vehicle speed:
N = F·V / 2 = 5 470·20.5 / 2 ≈ 56 000 W
Equilibrium Attained Net Force = 0 NewtonsDraw a free body diagram with a 10 N force and a 25 Newton force acting on an object in the opposite directions. Describe the additional force needed to be applied to achieve equilibrium.
Explanation:
There are two forces acting on the object in opposite directions.
The sketch of the two forces is
since the force acting towards the left is greater than the force acting on the right, the object will accelerate towards the left.
Now, how much force is required to counter 25 N acting on the left?
The answer is, if we apply an additional 15 N towards the right, the total force acting in this direction is 10 + 15 = 25 N, which is enough to counter 25 N acting towards the left.
Therefore, we need to apply an additional 15 N in the direction of the 10 N force.
A 75W outdoor lamp is connected to 240V source and left to turn on continuously for an average 14 hours per day. Determine:i) the current through the lamp when it is in operation.ii) the cost of operating the light for one year (365 days) if electricity costs in Malaysia is RM0.22 per kWh
We are given that a 75W lamp is connected to a 24V source. To determine the current passing through the lamp we will use the following formula:
[tex]P=VI[/tex]Where:
[tex]\begin{gathered} P=\text{ electric power} \\ V=\text{ voltage} \\ I=\text{ current} \end{gathered}[/tex]Now we plug in the given values:
[tex]75W=(240V)I[/tex]Now we divide both sides by 240 to solve for "I":
[tex]\frac{75W}{240V}=I[/tex]Solving the operation we get:
[tex]0.31A=I[/tex]Therefore, the current passing is 0.31 Ampere.
Now we will calculate the cost of operating the lamp for one year. To do that we will calculate first the number of hours the lamp will be connected for the year. Since the lamp is connected 14 hours a day, this means that in 365 days the number of hours is:
[tex]14\frac{hours}{day}\times365day=5110hours[/tex]Now we determine the kWh. To do that we will multiply the number of hours by the electrical power and we will divide the result by 1000 to convert the W into kW. We get:
[tex]75W\times\frac{1kW}{1000W}\times5110h=383.25kWh[/tex]Now we determine the cost by multiplying the kWh of the lamp by the cost per kWh:
[tex]0.22\frac{RM}{kWh}\times383.25kWh=84.32RM[/tex]Therefore, the cost of operating the lamp for a year is 84.32 RM:
a car is speeding down your street at a constant rate of 45 meters per second what is the net force acting on the car?
There is no acceleration if the velocity remains constant. In other words, the acceleration value is 0.
Why does a car accelerate while moving at constant velocity but not when moving at constant speed?The rate at which an object's velocity (speed and direction) varies is known as acceleration. Therefore, even though an object's speed is constant, it can accelerate if its direction does.
The automobile presses on your back as it accelerates you as it speeds up. Your body has a forward inertia (tendency to continue travelling at the same speed) that causes you to continue moving until the force of your seat belt causes you to slow down at the same pace as the vehicle.
In both the horizontal and vertical axes, the net force acting on the car must be zero. However, a constant force is required to keep it travelling at a constant speed, hence the net force vertically must be zero.
learn more about net force refer
https://brainly.com/question/25239010
#SPJ13
A student tries to unscrew a bolt with a spanner with 25 cm long. Thelargest force that he is able to apply is 100 N, while the minimummoment required to unscrew the nut is 30 N m. Can he unscrew the nut?
ANSWER
No, he cannot
EXPLANATION
First, let us draw a sketch of the problem:
For him to be able to unscrew the nut, the moment of the largest force he can apply must be greater than the minimum moment required to unscrew the nut.
To find the moment of the force, we apply the formula:
[tex]M=F\cdot d[/tex]where F = force applied = 100 N;
d = distance between effort and bolt i.e. the length of the spanner = 25 cm = 0.25 m
Therefore, we have that the moment of the force is:
[tex]\begin{gathered} M=100\cdot0.25 \\ M=25Nm \end{gathered}[/tex]Since the largest moment is 25Nm, and the minimum moment required to unscrew the nut is 30Nm, he cannot unscrew the nut.
The answer is NO.
What type of evidence do you think would be most difficult to collect? Why?
Answer: I think the evidence that would be most difficult to record and find would be trace evidence.
Explanation: I think trace evidence is the hardest type of evidence to collect. Trace evidence would be most difficult to collect because they are often small evidence like blood or hair.
A mover pushes a 20 kg crate across a level floor with a force of 200 N, but the crate accelerates at a rate of only 7.5 m/s2 because a friction force opposes the crate's motion. What is the magnitude of this force of friction?Force of FrictionA. 50 NB.100 NC. 15 ND. 25 N
ANSWER
[tex]A\text{.}50N[/tex]EXPLANATION
Parameters given:
Mass of crate, m = 20 kg
Force of push, F = 200 N
Acceleration of crate, a = 7.5 m/s²
To find the force of friction, we have to apply the net force acting on a body. The sum of all forces acting on the crate is equal to the product of its mass and its acceleration.
Therefore, we have:
[tex]F_{\text{net}}=F-F_f[/tex]where Ff = force of friction
Therefore, we have that:
[tex]\begin{gathered} m\cdot a=200-F_f \\ 20\cdot7.5=200-F_f \\ 150=200-F_f \\ \Rightarrow F_f=200-150 \\ F_f=50N \end{gathered}[/tex]That is the force of friction. (Option A)
Anyone, help me plss
The acceleration of the given car is 4 m/s² on the Right hand side.
What is meant by velocity?Velocity can be defined as the rate at which something moves in a specific direction.
As the speed of a car driving north on a highway or the pace at which a rocket takes off. Because the velocity vector is scalar, its absolute value magnitude will always equal the motion's speed.
Based on the information, one could use the following formula to compute the magnitude of acceleration in this case:
[tex]$a=\frac{V_f-V_i}{t}$$[/tex]
Given:
initial velocity (u): 2m/s
Final velocity (v): 12m/s
Time taken : 2.5 second
we know that,
V = u + at
after putting all the values, we get
a = 4 m/s²
To learn more about velocity, refer to:
https://brainly.com/question/25749514
#SPJ9
A particle’s position along the x-axis is described byx(t) = A t + B t2,where t is in seconds, x is in meters, and the constants A and B are given below.Randomized VariablesA = -3.15 m/sB = 2.4 m/s21 what is the position of the particle when the velocity is zero.
Given data:
Position of the particle along the x-axis;
[tex]x(t)=At+Bt^2[/tex]Here, A and B are constants with A=-3.15 m/s and B=2.4 m/s².
Therefore,
[tex]x(t)=-3.15t+2.4t^2[/tex]The velocity of the particle is given as,
[tex]v(t)=\frac{dx(t)}{dt}[/tex]Substituting x(t),
[tex]\begin{gathered} v(t)=\frac{d}{dt}(-3.15t+2.4t^2) \\ =\frac{d}{dt}(-3.15t)+\frac{d}{dt}(2.4t^2) \\ =-3.15+2\times2.4t \\ =-3.15+4.8t \end{gathered}[/tex]The time when the velocity will be zero is calculated by substituting v(t)=0 in the above expresion,
[tex]\begin{gathered} 0=-3.15+4.8t \\ 4.8t=3.15 \\ t=\frac{3.15}{4.8} \\ \approx0.66\text{ s} \end{gathered}[/tex]Therefore, the position of the particle when the velocity is zero is calculated by substituting t=0.66 s in the equation for the position of the particle,
[tex]\begin{gathered} x(0.66\text{ s})=-3.15\times0.66+2.4\times(0.66)^2 \\ \approx-1.03\text{ m} \end{gathered}[/tex]Therefore, the position of the particle when the velocity is zero is -1.03 m (1.03 m to the left of its initial position).
calculate the work done by gravity as a 3.9 kg object is movies from point A to point B , in figure along paths 1,2 and 3
Answer:
-76.44 J
Explanation:
The force due to gravity is conservative, it means that no matter the path, the work done from A to B will be always the same and it depends on the vertical distance between A and B which in this case is 2.0 m.
So, the work done by the gravity is
W = Fdcosθ
Where the force is the weight so, F = mg = (3.9 kg)(9.8 m/s²) = 38.22 N
d is the vertical distance, so , d = 2.0 m
And θ is the angle between the displacement and the weight, so, θ = 180
Then,
W = (38.22N)(2.0 m)cos(180)
W = -76.44 J
Therefore, the work done by gravity along paths 1, 2, and 3 was -76.44 J
Why can your contact with both very hot and very cold objects cause skin burns?
Contact with very cold objects cause skin burns because skin cells freeze, forming sharp ice crystals that can damage the skin cell structure.
contact with very hot objects cause skin burns because there are tissue damage that results from heat exposure to the skin.
What is the skin?The h skin is the outer covering of the body and is the largest organ of the integumentary system.
The skin also serves as a protective shield against heat, light, injury, and infection.
There are symptoms associated with damage or burn to the skin, which includes;
numbnesspainred, dark, white or grey skintinglingblistersLearn more about the skin at: https://brainly.com/question/306377
#SPJ1
