Answer:
A
Explanation:
When coal is burned it releases many harmful chemicals into the air, such as methane (greenhouse gas) and contributes to global warming
Why does a stop sign appear red?
Answer:
because it’s suppose to be red like a stop light.
Explanation:
So it tells you to stop
Mary and John are seated on a bench a distance 2 part. Suddenly, John moves closer to Mary and claims that he has been drawn by the gravitational force. Is John’s claim justifiable? Show quantitatively. (Assume the masses of John and Mary are 67 and 55 respectively, and the coefficient of static friction between John and the bench is 0.15). [4]
Answer:
no
gravitational force between them is far smaller than the frictional force between the guy and the bench
if an atom has two protons and three electrons than the atom is
Answer:
negative 1 charge
Explanation:
one electron is extra so there will be -1 chargw
If an atom has two protons and three electrons than the atom is negatively charged.
What is an atom?An atom is a matter particle that defines a chemical element uniquely. An atom is made up of a central nucleus and one or more negatively charged electrons.
The nucleus is positively charged and contains one or more protons and neutrons, which are relatively heavy particles.
It is made up of protons, which have a positive charge, and neutrons, which do not have any charge. Protons, neutrons, and the electrons that surround them are long-lived particles found in all natural atoms.
The modern atomic hypothesis was founded by John Dalton, a great chemist. His atom, on the other hand, was like a solid billiard ball.
An atom is negatively charged if it has two protons and three electrons.
Thus, the given atom bears negative charge.
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Please help meeeee
For a velocity versus time graph how do you know what the velocity is at a certain time? How do you know the acceleration at a certain time?
Answer:
Explained below
Explanation:
For a velocity time graph, the y - axis will represent velocity while the x - axis will represent time.
Now, to calculate velocity at a certain time t, we will draw a perpendicular line from the time on the x-axis to the graph line and trace the horizontal line from that point to the y-axis which will give the corresponding velocity at that time.
Now, for the acceleration at a time t. After getting the velocity like explained above, we now divide the velocity by the time.
A particular engine has a power output of 5 kW and an efficiency of 30%. If the engine expels 6464 J of thermal energy in each cycle, find the heat absorbed in each cycle. Answer in units of J.
Answer:
The heat absorbed in each cycle is 9,234.286 J
Explanation:
Given;
power output, P = 5 kW = 5,000 W
efficiency of the engine, e = 30 % = 0.3
thermal heat expelled, [tex]Q_c[/tex] = 6464 J
let the heat absorbed = [tex]Q_h[/tex]
The efficiency of the engine is given as;
[tex]e = \frac{W}{Q_h} = \frac{Q_h-Q_c}{Q_h} = \frac{Q_h}{Q_h} - \frac{Q_c}{Q_h} = 1-\frac{Q_c}{Q_h}\\\\e = 1-\frac{Q_c}{Q_h}\\\\0.3 = 1-\frac{Q_c}{Q_h}\\\\\frac{Q_c}{Q_h} = 1-0.3\\\\\frac{Q_c}{Q_h} = 0.7\\\\Q_h = \frac{Q_c}{0.7} \\\\Q_h = \frac{6464}{0.7} = 9,234.286 \ J.[/tex]
Therefore, the heat absorbed in each cycle is 9,234.286 J.
A swimmer speeds up from 1.1 m/s to 3.2 m/s during the last 13.0 seconds of the race. What is the acceleration of the swimmer?
Answer:
a = 0.16 [m/s²]
Explanation:
To solve this problem we must use the following equation of kinematics.
[tex]v_{f}=v_{o}+a*t\\[/tex]
where:
Vf = final velocity = 3.2 [m/s]
Vo = initial velocity = 1.1 [m/s]
t = time = 13 [s]
a = acceleration [m/s²]
Now replacing:
[tex]3.2=1.1+a*13\\2.1=13*a\\a=0.16[m/s^{2} ][/tex]
A diffraction pattern is formed on a screen 150 cm away from a 0.500-mm-wide slit. Monochromatic 546.1-nm light is used. Calculate the fractional intensity I/Imax at a point on the screen 4.10 mm from the center of the principal maximum.
Solution :
The expression for the intensity of light is given by :
[tex]$I=I_{max}\left(\frac{\sin \frac{\pi a \sin \theta}{\lambda}}{\frac{\pi a \sin \theta}{\lambda} }\right)^2$[/tex]
For a small angle, θ
sin θ = tan θ
[tex]$=\frac{y}{L}$[/tex]
Therefore the above equation becomes,
[tex]$I=I_{max}\left(\frac{\sin \frac{\pi a y}{\lambda L}}{\frac{\pi a y}{\lambda L} }\right)^2 $[/tex]
The given data is
λ = 546.1 nm
L = distance between the slit and the screen = 140 cm
= 1.40 m
a = width of the slit
= [tex]$0.50 \times 10^{-3} \ m$[/tex]
Therefore,
[tex]$I=I_{max}\left(\frac{\sin \frac{\pi \times 0.50 \times 10^{-3} \times 4.10 \times 10^{-3}}{546.1 \times 10^{-9} \times 1.20}}{\frac{\pi \times 0.50 \times 10^{-3} \times 4.10 \times 10^{-3}}{546.1 \times 10^{-9} \times 1.20} }\right)^2 $[/tex]
[tex]$=\left(\frac{0.170}{9.82}\right)^2$[/tex]
[tex]$= 2.89 \times 10^{-4} \ I_{max}$[/tex]
Therefore the fractional intensity is [tex]$\frac{I}{I_{max}}= 2.89 \times 10^{-4} $[/tex]
Two wave pulses pass each other on a string. The pulse traveling toward the right has positive amplitude, whereas the pulse traveling toward the left has equal amplitude in the negative direction. What happens when they occupy the same region of space at the same time?
a. constructive interference occurs
b. destructive interference occurs.
c. a standing wave is produced.
d. a traveling wave is produced.
e. a wave pulse is produced.
Answer:
destructive interference occurs
what is the main cause of seafloor spreading?
Answer:
As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense.
Explanation:
Answer: The main cause of sea floor spreading are the directions and force of the moving tectonic plates.
Explanation:
Energy stored because of an object's height above the Earth's surface is_____energy.
nuclear
gravitational
electrical or chemical
Thomas the Tank Engine (a train) is going 80 m/s and slows down to 30 m/s over a period of 30s. What is his deceleration? Acceleration= (final velocity-initial velocity)/ time A. -1.67 m/s/s B. 0.67 m/s/s C. -50 m/s/s D. 50 m/s/s
Answer: D
Explanation:
Plz help
Fill in the blank with the correct observation from the simulation.
As the days go on, the distance that the moon is from the sun in the night sky
A. Stays the same
B. Decreases
C. Increases
Starting at New Moon, The visual distance increases for about 2 weeks, then decreases for about the next 2weeks, until the next New Moon.
On the average, it changes by about 12° per day.
A person holds a ladder horizontally at its center. Treating the ladder as a uniform rod of length 4.15 m and mass 7.98 kg, find the torque the person must exert on the ladder to give it an angular acceleration of 0.396 rad/s2.
Answer:
4.535 N.m
Explanation:
To solve this question, we're going to use the formula for moment of inertia
I = mL²/12
Where
I = moment of inertia
m = mass of the ladder, 7.98 kg
L = length of the ladder, 4.15 m
On solving we have
I = 7.98 * (4.15)² / 12
I = (7.98 * 17.2225) / 12
I = 137.44 / 12
I = 11.45 kg·m²
That is the moment of inertia about the center.
Using this moment of inertia, we multiply it by the angular acceleration to get the needed torque. So that
τ = 11.453 kg·m² * 0.395 rad/s²
τ = 4.535 N·m
The Torque will be "4.535 N.m".
Given:
Mass of ladder,
m = 7.98 kgLength of ladder,
L = 4.15 m
The moment of inertia will be:
→ [tex]I = \frac{mL^2}{12}[/tex]
[tex]= \frac{7.98\times (4.15)^2}{12}[/tex]
[tex]= \frac{7.98\times 17.2225}{12}[/tex]
[tex]= 11.45 \ kg.m^2[/tex]
hence,
The torque will be:
→ [tex]\tau = 11.453\times 0.395[/tex]
[tex]= 4.535 \ N/m[/tex]
Thus the above approach is correct.
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. Emily pushes a 38.8 kg grocery cart of groceries by exerting a 76.0 N force on the handle inclined at 40.0 degrees below the horizontal. What are:
a. The horizontal and vertical components of Emily’s force
b. The acceleration of the cart?
Answer:
a) [tex]F_{x} = 58.2 N[/tex]
[tex] F_{y} = 48.9 N [/tex]
b) a = 1.5 m/s²
Explanation:
a) The horizontal and vertical components of Emily's force can be found knowing the angle and the exerted force.
Since the handle is inclined at 40.0° below the horizontal we have:
[tex] F_{x} = |F|*cos(\theta) = 76.0 N*cos(40) = 58.2 N [/tex]
[tex] F_{y} = |F|*sin(\theta) = 76.0 N*sin(40) = 48.9 N [/tex]
b) The acceleration of the car can be calculated as follows:
[tex] F_{x} = ma [/tex]
We used the horizontal component of the force because the cart is moving in that direction.
[tex] a = \frac{F_{x}}{m} = \frac{58.2 N}{38.8 kg} = 1.5 m/s^{2} [/tex]
Hence, the acceleration of the car is 1.5 m/s².
I hope it helps you!
you pick up a 3.8 kg can of paint from the ground a lift it to a height of 1.4 m. you hold the can stationary for half a minute, waiting for a friend on a ladder to take it. how much work do you do duting this time (when the can of paint is stationary)?
Answer:
No work
Explanation:
During the time of holding the can stationary, no work is being done by the person carrying the can.
The can is simply at rest.
Work is done when a force is applied to move a body through a certain distance.Work done = force x distance
In the instance given in this problem, only when the paint was lifted up is work done.
When the paint is stationary and being supported by the person, no work is done.
The scientific method can easily be misinterpreted as ___________. Question 1 options: a great magical trick, or slide of hands, rather than factual an "auto mechanics" guide to Science Investigation a "cookbook" recipe for performing scientific investigations the perfect method for finding the answers to all questions
Answer:
I think the answer is
a "cookbook" recipe for performing scientific investigations
Explanation:
define electric potential at a point and find expression for it.
Answer:
Recall that the electric potential is defined as the potential energy per unit charge, i.e. V=PEq V = PE q . ... The equation for the electric potential due to a point charge is V=kQr V = kQ r , where k is a constant equal to 9.0×109 N⋅m2/C2.
Explanation:
A 3 kg mass is travelling in a circle of 0.1 m radius with a speed of 2 m/s. What is the centripetal acceleration?
a = v² / R = (2 m/s)² / (0.1 m) = 40 m/s²
How does light move?
Answer:
Light travels as a wave. But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuum—a completely airless space. It speeds through the vacuum of space at 186,400 miles (300,000 km) per second.
Explanation:
Hope this helps :))
If 65 kW is to be transmitted over two 0.100 ohm lines, estimate how much power is saved if the voltage is stepped up from 120 V to 1200 V
Answer: 5.91kw
Explanation:
given data:
power = 65kw
voltage stepped up = 120v t0 1200
R 0.100
Solution:
when the it is stepped to 120v
[tex]P = VI \\65000/ 120I\\ I = 541.7A\\[/tex]
power loss
[tex](I^{2} )R*2\\= (541.7^{2})0.100*2\\= 58536.2w[/tex]
when it is stepped to 1200v
[tex]\frac{65000}{1200} \\ I = 54.17A\[/tex]
[tex](I^{2} )R*2\\= (54.17^{2})0.100*2\\= 586.9w[/tex]
total power saved
[tex]= 65kw - 58.5kw - 0.59kw\\= 5.91kw[/tex]
A student adds two vectors of magnitudes 48 m and 22 m. What are the maximum and minimum possible values for the resultant of these two vectors.
Answer:
Maximum=70 m
Minimum=26 m
Explanation:
Vector Addition
Since vectors have magnitude and direction, adding them takes into consideration not only the magnitudes but also their respective directions. Two vectors can be totally collaborative, i.e., point to the same direction, or be totally opposite. In the first case, the magnitude of the sum is at maximum. Otherwise, it's at a minimum.
Thus, the maximum magnitude of the sum is 48+22 = 70 m and the minimum magnitude of the sum is 48-22= 26 m
if a certain car, going with speed v1, rounds a level curve with a radius r1, it is just on the verge of skidding. if its speed is now doubled, the radius of the tightest curve on the same road that it can round without skidding is:
Answer:
The correct answer is 4R1
Explanation:
According to the given scenario ,the radius of the tightest curve on the same road without skidding is as follows:
As we know that
Centeripetal Acceleration is
= v^2 ÷ r
In the case when velocity becomes 2 times so the r would be 4 times
So, the radius of the tightest curve on the same road without skidding is 4R1
What causes the magnetic field around the wire?
Magnetic field
O A. An electric current
O B. An electric field
PREVIOUS
An electric current causes the magnetic field around the wire. The correct answer is A.
The magnetic field around a wire is caused by the flow of electric current through the wire. When an electric current passes through a wire, it generates a magnetic field that forms circular lines of magnetic flux around the wire. This phenomenon is described by Ampere's law, which states that a magnetic field is produced by an electric current and its strength is directly proportional to the magnitude of the current.
The relationship between the electric current and the magnetic field can be understood using the right-hand rule. If you wrap your right hand around the wire with your thumb pointing in the direction of the current, the curled fingers indicate the direction of the magnetic field lines.
Therefore, an electric field is generated by an electric charge, not by an electric current. While an electric field can exist around a wire if there is a potential difference (voltage) applied across it, it is the flow of electric current that primarily generates the magnetic field.
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HELP right awayyy !!!
Answer:
Question 4 is actually Acceleration