18. What is the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s? A. 6,000 J B. 5,880 J C. 2,940 J D. 12,000 J
Answer: 6,000 J
Explanation:
what essential characteristic does a good experiment have? a. a control group is given the experimental treatment. b. a single variable is tested. c. a control is used. d. both b and c
A good experiment should have a control and test a single variable.
Explanation:A good experiment should have the essential characteristic of using a control to compare the results of the experimental treatment. This ensures that any changes or effects seen in the experimental group can be attributed to the treatment being tested and not to other factors. Additionally, a good experiment should test a single variable to isolate the specific factor being studied.
For example, if a scientist is testing the effect of a new fertilizer on plant growth, they would have two groups of plants - one receiving the new fertilizer (experimental group) and one receiving no fertilizer (control group). By comparing the growth of the two groups, they can determine if the fertilizer had any effect.
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Rarefaction occurs only in a ___ wave.
A: transverse
B: longitudinal
C: sympathetic
D: forced
Answer:B: longitudinal
Explanation:
At 16, Juana is at an appropriate weight and likes to eat whatever she wants to.
What's the best strategy to ensure Juana's health?
Answer:
Regular exercise, play some sport, take healthy diet.
Explanation:
(1) She should walk one time in a day for like 30 minutes or more and will pay attention towards her diet to prevent further weight gain
(2) She can engage herself in aerobic exercises and start taking the food that is rich in nutrients and fiber
.
(3) She can play aerobic sport like soccer and can reduce her calorie intake to 1850 per day.
These are the best strategies she can adopt to ensure her heath.
When rubbed against a silk cloth, a glass rod loses electrons. How does this affect the charges of the glass rod and the silk cloth?
Answer: The glass rod becomes positively charged while the silk cloth becomes negatively charge
Explanation:
When you are rubbing the glass rod with a silk cloth,electrons escapes from the atoms of the glass rod, this the glass rod loses electrons and it is gained or accepted by the silk cloth,thus making the silk cloth negatively charged and the glass roof positively charged.
The net charges are equal and opposite charges on both materials.
Which of the following is not an application of Doppler technology?
police speed guns
weather radar
ultrasound imaging of the liver
determining the motion of a star
Answer:
ultrasound imaging of the liver.
Explanation:
Liver ultrasound is not an application of the Doppler effect. The use of ultrasound is more common in medicine, for example, during pregnancy.
Another application in medicine is with the movement of blood. It is a flowmeter which allows the blood flow to be discovered through the Doppler effect, since a sound wave affects the red blood cells that are in motion inside the vessel and collect the echo signal.
When you add heat energy the molecules move ______ and _____
Ow does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?
Which would usually be studied by a geologist
Wave C has an amplitude of 1 and wave D has an amplitude of 3 as shown below. What will happen when the trough of wave C meets the crest of wave D?
They will interfere to create a crest with an amplitude of 4.
They will interfere to create a crest with an amplitude of 2.
They will interfere to create a crest with an amplitude of 0.
They will bounce off each another.
Answer:
They will interfere to create a crest with an amplitude of 2.
Explanation:
The two waves will interfere and the resultant amplitude will be given by the principle of superposition, which states that the resultant amplitude is given by the sum (or the difference, if they meet in opposite phase) of the amplitudes of the two waves. In this case, the crest of wave C meets the through of wave D, so they are in opposite phase, therefore the resultant amplitude will be
A = A(C) - A(D) = 3 - 1 = 2
Ignoring effects caused by differences in depth, the pressure in a contained fluid is __________.
a. the same throughout the fluid
b. higher in some places and lower in other places
c. unknown as long as the fluid is contained
Which example best represents an object with balanced forces acting upon it? A) A boat moving through the water. B) A book sitting on a high shelf. C) A wagon rolling down a steep hill. D) A baseball thrown thrown in the air.
An example that best represents an object with balanced forces acting upon it is a book sitting on a high shelf. Thus, the correct option for this question is B.
What do you mean by Force?Force may be defined as the process of pushing and pulling an object with an actual mass that stimulates its velocity to be changed. It is a type of vector quantity because it has both magnitude and direction.
It is the simple and fundamental concept of physics that when two or more objects are interacting with one another but do stimulate any change in their position.
The principle is applied in this question where a book is exerting pressure in a downward direction while a shelf is exerting pressure in an upward direction and resulting in an equal and opposite force.
Therefore, a book sitting on a high shelf is an example that represents an object with balanced forces acting upon it. Thus, the correct option for this question is B.
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Calculate the moment of inertia of uniform circular disc of mass 500g, radius 10cm about 1.the diameter of the disc. 2. the axis tangent to the disc parallel to its diameter 3.the axis through the center of the disc and perpendicular to its plane
Mass of the disc is equal to 500 g (m=500 g)
Radius of the disc if equal to 10 cm (r=10 cm)
1. The diameter of the disc:
D = 1/4 (m) (r)^2
= 1/4 (500) x 10^2 g cm^2
= 12500 g cm^2
2. The axis tangent to the disc and parallel to its diameter:
= 1/4 (m) (r )^2 + m (r )^2
= 5/4 x 500 x 10^2 g cm^2
= 62500 g cm^2
3. The axis through the center or the disc and perpendicular to its plane:
= 1/2 (m) (r )^2 – ½ x 500 x 10^2 g cm^2
= 25000 g cm^2
The moment of inertia for the disc about its diameter is 0.0025 kg.m², the moment of inertia about an axis tangent to the disc parallel to its diameter is 0.0075 kg.m², and the moment of inertia about an axis through the center and perpendicular to the disc's plane is 0.005 kg.m².
Explanation:The moment of inertia (I), a measure of an object's resistance to rotational motion about an axis, varies depending upon the axis of rotation. Various formulae apply for different axes:
About the diameter of the disc: Here, the formula is I = 1/2 ×m ×R², where m is the mass and R is the radius. Substituting the provided values(m = 500g = 0.5kg, R = 10cm = 0.1m), we find that the moment of inertia about the diameter is I = 1/2 ×0.5kg × (0.1m)² = 0.0025 kg.m².The axis tangent to the disc parallel to its diameter: For this case, we would use the parallel axis theorem: I = I_center of mass + m×d². Here, d is the distance from the center of mass to the new axis, which equals the radius (R). Since the moment of inertia about the diameter (I_center of mass) is 0.0025kg.m², the moment of inertia for this axis is I = 0.0025 kg.m² + 0.5kg × (0.1m)² = 0.0075kg.m².The axis through the center of the disc and perpendicular to its plane: Here, the formula is I = m × R². Substituting the given values, we find the moment of inertia is I = 0.5kg × (0.1m)² = 0.005 kg.m².Learn more about Moment of Inertia here:https://brainly.com/question/30051108
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how long will it take to travel 200,000m traveling 10m/s
Based on the data you found, about how many of the 100 aliens would become thin if the temperature were 35°C?
Answer:Option D: More than 90
Explanation:Thickness probably depends on temperature. The higher the temperature, the more aliens we expect to be thin.
Which statement about the greenhouse effect is NOT true?
A) The greenhouse effect keeps Earth from becoming too hot during the day.
B) The greenhouse effect causes the change in seasons.
C) The greenhouse effect keeps Earth from becoming too cold during the night.
D) The greenhouse effect makes it possible for organisms to live on Earth.
E) The greenhouse effect can be influenced by human activity.
Answer: D). The greenhouse effect makes it possible for organisms to live on Earth.
Explanation:
Greenhouse effect is a phenomena which depicts the fact that the heat energy from the earth does not reflect back to the space which has been obtain from the sun. This is caused by the greenhouse gases which traps the heat energy from sun making the atmosphere hot.
This results in fluctuations in climatic conditions. Responsible for melting of glaciers hence, the organisms which are adapted to survive in glaciers will not be able to survive in hot climatic conditions. Also the organisms living in the terrestrial regions cannot tolerate excess heat and will die.
What is the pressure of a 59.6-l gas sample containing 3.01 mol of gas at 44.9°c? (r = 0.0821 l • atm/(k • mol), 1 atm = 760 torr)?
Final answer:
The pressure of a 59.6-l gas sample containing 3.01 mol of gas at 44.9°C is approximately 1.31 atm or 995.6 torr, calculated using the ideal gas law equation.
Explanation:
To find the pressure of a gas sample, which contains 3.01 mol of a gas at a volume of 59.6 L and a temperature of 44.9°C, we can use the ideal gas law: PV = nRT. First, we need to convert the temperature to Kelvin by adding 273.15 to the Celsius temperature, giving us a temperature of 318.05 K. Using the given constant R = 0.0821 L • atm/(K • mol), we can rearrange the ideal gas law to solve for P (pressure).
The calculation is as follows:
P = (nRT) / V
P = (3.01 mol × 0.0821 L • atm/(K • mol) × 318.05 K) / 59.6 L
P ≈ 1.31 atm
Converting this to torr using the conversion 1 atm = 760 torr, we have:
P ≈ 1.31 atm × 760 torr/atm
P ≈ 995.6 torr
If i measure the parallax of a star to be 0.125 arc seconds, what is its distance in parsecs?
To compute for the distance of a star given the parallax, we simply have to take the reciprocal of the magnitude of parallax. In this case, distance is:
distance = 1 / parallax
distance = 1 / 0.125
distance = 8 parsecs
During an exothermic process, _____. during an exothermic process, _____. no heat is exchanged between the system and the surroundings the system feels cold to the touch heat flows from the system to the surroundings heat flows from the surroundings to the system
which weights would you use on a single thread to create a 6.86N force
6.86 N = (mass) x (9.8 m/s²)
Mass = (6.86 N) / (9.8 m/s²)
Mass = (6.86 kg-m/s²) / (9.8 m/s²)
Mass = (6.86/9.8) kg
Mass = 0.7 kilogram
I would use the 500-gram weight and the 200-gram weight, and hang them both from the end of the thread. Then the total mass on the end of the thread is 700 grams. When I take it to Earth, it will weigh 6.86 N .
Lydia is often described as having a positive outlook on life. She assumes the best of people and situations. Lydia exemplifies ________.
Answer:
Optimism.Explanation:
Optimism could be defined as a spiritual and mental disposal for positive outcomes, refers to the best future coming, the opposite of pessimism.
A optimistic person is who have a positive view of situation, even if it isn't seem like that, even these kind of people see positiveness in others, like Lydia.
The force of gravity follows an inverse square law, meaning that the strength of the force declines with the square of the distance between two masses. but if the distances between pairs of objects are all the same, as in part a, then the strength of gravity depends only on
_____ is the kinetic energy of an object, proportional to the object's moment of inertia and the square of its angular velocity.
You throw a ball downward from a window at a speed of 2.5 m/s. how fast will it be moving when it hits the sidewalk 2.1 m below?
Ava has just learned to tell her teacher how many markers are in the set by counting each one and saying the last number as the answer to “How many?” Ava is most likely ________ year(s) old.
Answer:
Explanation:
Ava is a child who probably got admission into the school and has learned to count.
Her age can be between 3-4 as in this age toddlers get admission or they start to learn to basic counting.
She is just counting the number of markers and as per her the answer of "how many" means the last number she has counted. She is probably too little.
A girl sits on a tire swing and is pushed in a circular motion by her father. Her tangential speed is 2.8 m/s and the girl travels in a circle with a diameter of 4.0 m. What is the girl's centripetal acceleration?
Answer:
[tex]a_c = 3.92 m/s^2[/tex]
Explanation:
tangential speed of the girl is given as
[tex]v_t = 2.8 m/s[/tex]
diameter of the circle is given as
[tex]d = 4.0 m[/tex]
so here the radius of the circle is given as
[tex]R = 2.0 m[/tex]
now we know that centripetal acceleration of the object moving in circle is given as
[tex]a_c = \frac{v^2}{R}[/tex]
[tex]a_c = \frac{2.8^2}{2}[/tex]
[tex]a_c = 3.92 m/s^2[/tex]
An elevator releases 10,000 j of gravitational potential en-ergy while descending 5 m between fl oors. how much does the elevator weigh?
The weight of the elevator is approximately 204.08 kg.
To calculate the weight of the elevator, we can use the formula for gravitational potential energy:
[tex]\[ PE = mgh \][/tex]
Given that the elevator releases [tex]\( 10,000 \)[/tex] J of gravitational potential energy while descending [tex]\( 5 \)[/tex] m between floors, we can rearrange the formula to solve for the mass [tex]\( m \)[/tex] of the elevator:
[tex]\[ m = \frac{PE}{gh} \][/tex]
Given:
[tex]\( PE = 10,000 \)[/tex] J (gravitational potential energy)
[tex]\( g = 9.8 \) m/s\(^2\)[/tex] (acceleration due to gravity)
[tex]\( h = 5 \)[/tex] m (height change)
Substituting the given values into the formula:
[tex]\[ m = \frac{10,000 \, \text{J}}{9.8 \, \text{m/s}^2 \times 5 \, \text{m}} \][/tex]
[tex]\[ m = \frac{10,000}{49} \, \text{kg} \][/tex]
[tex]\[ m \approx 204.08 \, \text{kg} \][/tex]
Therefore, the weight of the elevator is approximately [tex]\( 204.08 \)[/tex] kg.
Given 10,000 J of energy and a 5 m descent, the weight of the elevator is found to be 2000 N.
To determine the weight of the elevator, we can use the formula for gravitational potential energy, which is given by:
Gravitational Potential Energy (GPE) = mgh
where:
m is the mass of the elevator in kilograms
g is the acceleration due to gravity (approximately 9.8 m/s² on Earth)
h is the height in meters
We know that the change in gravitational potential energy is 10,000 J and the height difference is 5 m. Rearranging the formula to solve for the weight (mg), we get:
GPE = mgh
Weight = mg = GPE / h
Weight = 10,000 J / 5 m
Weight = 2000 N
Therefore, the elevator weighs 2000 Newtons.
what i the distance that light moves in a year called
nocturnal year
solar year
planetary year
light-year
Answer:
correct answer is - light year
Explanation:
Describe what occurs at a destructive boundary. Explain what folding is and give an example of a mountain region formed by folding. this is for earth science btw
What is the value of g on the surface of saturn? assume msaturn = 5.68×1026 kg and rsaturn = 5.82×107 m?
The value of gravity on the surface of Saturn can be calculated using the universal law of gravitation. Knowing Saturn's mass and radius, the calculation provides a result of around 10.44 m/s^2 for the acceleration due to gravity.
Explanation:
To determine the value of gravity (g) on the surface of Saturn, you would use the universal law of gravitation. This law states that the force of gravity between two objects is equal to the gravitational constant (G), multiplied by the product of their masses, and divided by the square of the distance between them. In the case of finding the acceleration due to gravity on the surface of a planet, we usually simplify this equation to: 'g = GM/r^2', where M is the mass of the planet and r is the radius.
The gravitational constant, G, equals 6.67 x 10^-11 N(m/kg)^2. Knowing the mass of Saturn (5.68 x 10^26 kg) and its radius (5.82 x 10^7 m), the equation becomes: 'g = (6.67 x 10^-11 N(m/kg)^2 x 5.68 x 10^26 kg) / (5.82 x 10^7 m)^2'. Solving this, we find that the acceleration due to gravity on the surface of Saturn (g) is approximately 10.44 m/s^2.
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