Halfway though a cross-country meet,a runner’s speed is 4m/s.In the last stretch,she increases her speed to 7m/s.What is her change in speed?
Answer:
The change in speed is 3m/s
Explanation:
The change is speed is defined as the difference between final and initial speed:
ΔV=[tex]V_{2}-V_{1}[/tex]
where V2 and V1 are the final and initial speeds, respectively.
Plugging in the values
ΔV=7m/s-4m/s=3m/s
A current of 12 amps is measured in a circuit with a total resistance of 9.0 ohms. What is the size of the voltage source that supplies this circuit?
a. 108 volts
b. 21 volts
c. 1.3 volts
d. 0.75 volts
The pH of acid rain would be _____. greater than 7 less than 7 exactly 7 exactly 14
Answer:
Less than 7.
Explanation:
pH scale in chemistry is used to measure the concentration of hydrogen ion. In other words, it is used to measure the extent of acidity or alkalinity of any solution. The pH scale having numbers that range from 0 to 14. The acidic solution has a lower pH value while the basic solution has a higher pH. The pH value of pure water is 7.
As the name implies acid rain, it is formed by the combination of sulfur and nitrogen oxides. The pH of acid rain is less than 7. Typically its value is 4.
A ball is thrown downward at 5ms from roof 10m high its velocity when it reaches the ground is?,
If an object has a volume of 2 milliliters and a mass of 10 grams, calculate the density of the object.
If a neutral atom has a mass of 15 amu and an atomic number of 7, determine the number of protons, neutrons, and electrons in the atom.,
Wave A has an amplitude of 2, and wave B has an amplitude of 2. What will happen when the crest of wave A meets the trough of wave B?
They will interfere to create a crest with an amplitude of 0.
They will interfere to create a crest with an amplitude of 2.
They will interfere to create a crest with an amplitude of 4.
They will bounce off each another.
Answer:
They will interfere to create a crest with an amplitude of 0.
Explanation:
It is given that,
Wave A has an amplitude of 2, and wave B has an amplitude of 2. The superposition of two waves is called interference of wave. When the resultant wave have maximum amplitude is called constructive interference while when the amplitude of resultant completely destructs, the destructive interference happens.
When the crest of wave A meets the trough of wave B, then destructive interference occurs. the phase difference will be 180°. There resultant is given by :
[tex]R=\sqrt{A^2+B^2+2ABcos(180)}[/tex]
R = A - B
Here A = 2 and B = 2
⇒ R = 0
Hence, the correct option is (a) "They will interfere to create a crest with an amplitude of 0".
A solid uniform-density sphere is tied to a rope and moves (without spinning) in a circle with speed 7 m/s. The distance from the center of the circle to the center of the sphere is 1.8 m, the mass of the sphere is 6 kg, and the radius of the sphere is 0.89 m. The angular speed, w=5.62. What is the rotational kinetic energy of the sphere?,
The rotational kinetic energy of the sphere in a circular path (without spinning) is calculated using given parameters such as mass, radius, and angular speed, and the resultant rotational kinetic energy is approximately 227.03 Joules.
Explanation:Answer
For the sphere, when it moves in a circular path without spinning, its rotational kinetic energy (K) is zero, because there's no internal rotation where the points in the body are moving through some angle due to spinning. However, if you are considering the entire motion of the system, then you could argue that there's rotational kinetic energy due to the rotation of the center of the circle. This is really a translational motion but in a circular path. The rotational kinetic energy can then be calculated using the equation, K = 1/2 (mr^2)w^2, where m is the mass of the sphere, r is the distance from the center of the circle to the center of the sphere, and w is the angular speed (not the angular velocity of the sphere itself if it was spinning). Lastly, substituting the known values: m=6 kg, r=1.8 m, and w=5.62 rad/s, we find that K = 1/2 * (6kg) * (1.8m)^2 * (5.62 rad/s)^2 = 227.0268 Joules.
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The rotational kinetic energy of the sphere is 30.03 Joules. This is calculated using the formula [tex]KE_{rot} = 0.5 \times I \times w^2[/tex], where I is the moment of inertia of the sphere and w is its angular speed.
To find the rotational kinetic energy of the sphere, we use the formula for rotational kinetic energy: [tex]KE_{rot} = 0.5 \times I \times w^2[/tex].
Where:
I - moment of inertia of the spherew - angular speedFor a solid sphere, the moment of inertia is given by:
[tex]I = (2/5) \times m \times R^2[/tex]
Substituting the given values:
[tex]I = (2/5) \times 6 kg \times (0.89 m)^2\\I = (2/5) \times 6 kg \times 0.7921 m^2\\I = 1.901 kg\cdot m^2[/tex]
Now, using the angular speed w = 5.62 rad/s:
[tex]KE_{rot} = 0.5 \times 1.901 kg\cdot m^2 \times (5.62 rad/s)^2\\KE_{rot} = 0.5 \times 1.901 kg\cdot m^2 \times 31.5844 rad^2/s^2\\KE_{rot} = 30.03 J[/tex]
Therefore, the rotational kinetic energy of the sphere is 30.03 Joules.
Which of the following is true of energy? A. Energy can be created. B. Energy can be destroyed. C. Energy is constantly increasing. D. Energy is conserved.
What’s the force of a pitching machine on a baseball? Baseballs pitched by a machine have a horizontal velocity of 30 meters/second. The machine accelerates the baseball from 0 meters/second to 30 meters/second in 0.5 seconds. If a baseball has a mass of 0.15 kilograms, the force the machine exerts is newtons. Use F = ma, where .
Answer:
So F=ma
The acceleration of the baseball is:
where and are the final and initial speed of the ball, and is the time interval in which the force acted.
Replacing the numbers, we get
And at this point, we can use Newton's second law F=ma to find the value of the force of the pitching machine:
In which situation would an object weigh the LEAST? (assume all the objects have the same mass) A) an object on Earth Eliminate B) an object on the moon C) an object half-way between the Earth and moon D) an object in space closer to the moon than the Earth
Answer: The correct answer is D.
Explanation:
The object weigh less on the moon than Earth. The weight of the object on the moon is one sixth the weight of the object on the Earth.
Greater the mass of the object, greater will be the gravitational force. Then more will be the weight of the object. The mass of the moon is less than the mass of the earth. The object weigh less on the moon than Earth.
As you go away from the Earth's surface, the weight of the object will get reduce.
An object in space closer to the moon than the earth.
Therefore, an object in space closer to the moon than the Earth would weigh the least.
Plants use carbon dioxide for .
1. respiration
photosynthesis
which of the following best describes the noble gases?
have an outer electron shell that needs only 1 electron
are highly reactive
have a full outer electron shell
combine easily with other elements
The cliff divers at acapulco, mexico, jump off a cliff 17.2 m above the ocean. ignoring air resistance, how fast are the divers going when they hit the water?
Jessie draws a ray diagram to show how an image of a candle is produced by a concave mirror when the candle is placed in front of the center of curvature. Jessie thinks the image should be virtual and behind the mirror.
Which best describes Jessie’s error?
The object should be placed anywhere on the principal axis.
The object should be at the center of the curvature.
The object should be between the center and vertex.
The object should be between the focal point and vertex.
On Edge, the answer is D.
An earth satellite in an elliptical orbit travels slowest when it is
A satellite in an elliptical orbit around Earth moves slowest at its apogee, which is the point farthest from the Earth, due to the weaker gravitational force and conservation of angular momentum.
Explanation:An earth satellite in an elliptical orbit travels slowest when it is at the point farthest from the Earth, known as the apogee.
In an elliptical orbit, satellites experience varying speeds. The speed is greatest at the point closest to Earth, called perigee, and lowest at the apogee. This is due to the conservation of angular momentum and energy: while the gravitational pull is strongest at the perigee resulting in higher velocity, it is weakest at the apogee, hence causing the satellite to move slower.
Orbital dynamics, such as the one described, are dictated by Kepler's laws of planetary motion where among others, it states that a planet or satellite will sweep out equal areas in equal times, leading to a change in speed depending on its position along the orbit. Thus, as a satellite moves away from the Earth, to the apogee of its orbit, its orbital speed decreases due to the weaker gravitational force at that point.
A car with a mass of 1,500 kilograms is moving around a circular curve at a uniform velocity of 16 m/s. The curve has a radius of 100 meters. What's the centripetal force on the car?
Joan is setting up an experiment in the lab to observe newton's second law of motion. she has a model car that has a mass of 45 kg, and it is accelerating at 7 m/s/s. she then increases the acceleration to 28 m/s/s. what happens to the force of the car?
Answer:
4 times its original size
Explanation:
study island said so
Four wires meet at a junction. it is assumed that two currents, i1 and i4, enter the node. an ammeter records a value of +4a for i1. currents i2 and i3 are travelling out of the node. i2 has 3a running through it, and i3 has 0.5 a running through it. what is the current in i4?
How does the usable form of nitrogen enter our bodies?
A.)by breathing in air
B.)by consuming plants
C.)by consuming water
D.)by burning fuel
Answer: B.)by consuming plants
Explanation:
There is about 78% nitrogen is available in the atmosphere. But living beings such as plants does not absorb it directly from the air. Instead they absorb the compounds of nitrogen from the soil. The soil bacteria convert the nitrogen oxides into ammonia, nitrates and nitrites in the soil in this way these bacteria fix atmospheric nitrogen into the soil. The plants absorb these forms of nitrogen, which are essentially required for the synthesis of proteins and nucleic acids. Nitrogen as an element becomes essential ingredients in all biomolecules. We humans and animals eat plants and through them the usable form of nitrogen in the form of biomolecules enters the body.
Answer:
the correct answer is B. by consuming plants
Explanation:
What is one way you can destroy a magnet’s magnetism? a. by putting it in water b. by cooling it c. by heating it d. by breaking it into pieces
the answer is C LOLOLO
Light with a frequency of 7.18 Ã 1014 hz lies in the violet region of the visible spectrum. what is the wavelength of this frequency of light? answer in units of nm.
What is the magnitude of the electric force on an electron in a uniform electric field of strength 2050 n/c that points due east?
If a ball is tossed straight up into the air, at what position is its potential energy the greatest? Question 2 options: a) when it is at the top b) when it is getting near the top c) when it leaves your hand d) when it starts to fall back to your hand
Which best describes latitude
What best describes Latitude is ; The measure of the angular distance North and south of the equator at zero degrees
What is latitudeLatitude lines are horizontal lines which measures the angular distance north and south of the equator which is set at zero degrees, the latitudes measures the distance between th north pole and the south pole of the earth.
Hence we can conclude that What best describes Latitude is ; The measure of the angular distance North and south of the equator at zero degrees.
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Degausser creates a magnetic field that erases data from magnetic storage media.
a. True
b. False
Which of the following does the endocrine system regulate??
A. Hormones
B. Reflexes
C. Respiration
D. Senses
Answer: Your answer would be A Hormones
Hope this helped XD
Which describes the movement of a fluid during convection?
A. Warm and cool fluids rise.
B. Warm and cool fluids sink.
C.Warm fluid rises and cool fluid sinks.
D.Warm fluid sinks and cool fluid rises.
Hello there!
The hotter molecules would then become expanded and then they would then be warm and cool, and then the fluids would then rise. When the fluids such as gas for example, when they are warm and then cool, they would then rise, and this would be an example of a movement of a fluid during convection.
I hope this helps you! :)
A. Warm and cool fluids rise.
B. Warm and cool fluids sink.
C.Warm fluid rises and cool fluid sinks.
D.Warm fluid sinks and cool fluid rises.
I hope this helps you!
If you're taking the course on Edge, the answer is C.
When you hold a warm bowl, the temperature of your palms of your hands increases this is example of
If the Earth and distant stars were stationary (motionless) in space, what would we observe about the wavelength from these stars?
A.Wavelengths measured would match the actual wavelengths emitted.
B.Wavelengths measured would be shorter than the actual wavelengths emitted.
C.Wavelengths measured would be longer than the actual wavelengths emitted.
If a star is moving toward us in space, what would we observe about the wavelength from these stars?
A.Wavelengths measured would be shorter than the actual wavelengths emitted.
B.Wavelengths measured would match the actual wavelengths emitted.
C.Wavelengths measured would be longer than the actual wavelengths emitted.
Which is a drawback of agricultural technology?
A. Better communication
B. Prevents disease
C. Water pollution
D. Kills bugs