The first law states that the internal energy change of that system is given by Q − W . Since added heat increases the internal energy of a system, Q is positive when added to the system and negative when removed from the system.
1. List some environmental challenges identified by the Brundtland Commission's overview, as well as a key strategy for addressing them. Identify urgencies that the Commission sees as necessary for an optimistic environmental future.
The Brundtland Commission spotted as a matter of urgency, the interconnection between natural resource use and the economy.
What is the Brundtland Commission?The Brundtland Commission was set up with the intention to achieve sustainable development. The tenure of the commission lasted from 1984 to 1987.
The commission identified the pillars of sustainable growth as economic growth, environmental protection, and social equality. The committee opined that environmental problem emanates from poverty in the southern region and reckless consumption of resources in the northern region.
The Brundtland Commission spotted as a matter of urgency, the interconnection between natural resource use and the economy.
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which items can be classified as matter? check all that apply?
-pencil
-oxygen
-idea
-horse
-dream
Answer:horse
Explanation:
what happens when a force is applied to an object while the object moves in a direction opposite to the force?
a. negative work is done
b. work is done only if the force causes a decrease in speed
c. positive work is done
d. work is done only if the force causes an increase in speed.
Answer:
the anser is b
Explanation:
If the force applied on the object is in the direction of its motion, the speed of the object increases. If the force is applied in the direction opposite to the direction of motion, then it results in a decrease in the speed of the object.
How do we solve questions C and D? I already did A and B and I am confused on how to continue
(a) The work done in moving the unit charge from point C to A is 7.62 x 10⁻³ J.
(b) The work done in moving the unit charge from point D to B is 7.62 x 10⁻³ J.
Work done in moving the charge from C to A
W = Fd
W = Kq²/d
from 0 origin to C, d = √(5² + 5²) = 7.07 mfrom 0 origin to A, d = 5 mW(C to A) = W(0 to C) + W(0 to A)
[tex]W(C \ to \ A) = - \frac{Kq^2}{7.07} + \frac{Kq^2}{5} \\\\ W(C \ to \ A) = 0.0586 \ Kq^2\\\\W(C \ to \ A) = 0.0586 \times 9 \times 10^9 \times (3.8\times 10^{-6})^2\\\\W(C \ to \ A) = 7.62 \times 10^{-3} \ J[/tex]
Work done in moving the charge from D to Bfrom 0 origin to D, d = √(5² + 5²) = 7.07 mfrom 0 origin to B, d = 5 mW(D to B) = W(0 to D) + W(0 to B)
W(D to B) = 7.62 x 10⁻³ J
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The resistivity of pure water is fairly high, 1.8 × 105 Ω·m, whereas the resistivity of sea water is a million times lower, 2 × 10-1 Ω·m. Why does the high salt concentration make sea water significantly less resistive (i.e. more conductive) than pure water?
The high salt concentration make sea water significantly less resistive than pure water due to presence of charged ions in the sea water.
What is resistivity?The resistivity of a substance is the opposition to the flow of charges offered by the substance.
The greater the resistivity of a substance, the lesser its conductivity.
A high salt concentration make sea water highly conductive due to presence of charged ions in the water. The greater conductivity reduces the resistivity of the sea water.
A pure water has no charged ions in the water, thereby decreasing its conductivity and increasing its resistivity.
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Calculate the height of stairs a 60 kg student would have to run in order to burn off 1 Calorie of food energy, which is the equivalent of 4190 Joules.
The height of stairs a 60 kg student would have to run in order to burn off 1 Calorie of food energy will be 7.1 meters.
What is potential energy?The potential energy is due to the virtue of the position and the height. The unit for the potential energy is the joule.
Given data;
Mass of student,m = 60 kg
Energy,E = 4190 J
Height of stairs,h=?
The potential energy is mainly dependent upon the height of the object. The potential energy is found as;
Potential energy = mgh
E=mgh
h=E/mg
h= 4190 J / (60 kg× 9.81 m/s²)
h = 7.1 metre
Hence the height of the stairs will be 7.1 meters.
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A skier (m=55.0 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally.
a. If h = 6.50 m and D = 11.4 m, find H.
b. Find her total kinetic energy as she reaches the ground.
a. The value of H is 11.51 m
b. The total kinetic energy as she reaches the ground is 6.21 kJ.
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
Given is a skier (m=55.0 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally. Value of h = 6.50 m and D = 11.4 m.
Time taken to reach the ground after take off is
t = √2h/g
t = √(2x6.50) /9.81
t =1.15 s
The speed at that time is
speed = distance /time
v = 11.4 /1.15
v = 9.913 m/s
a. From energy conservation principle,
v = √2g(H-h)
Plug the values, we get
9.913 = √(2 x 9.81 (H - 6.5)
Squaring both sides and solving, we have
H = 11.51 m
Thus, the value of H is 11.51 m.
b. The energy at the ground will be only potential energy
Total kinetic energy at the ground = mgH
T.K.E = 55 x 9.81 x 11.51
T.K.E =6.21 kJ
Thus, the total kinetic energy is 6.21 kJ.
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what is the energy of a photon with a frequency of 8.34 x 10^14 hz, in joules?
Answer:
E = 5.52 x 10⁻¹⁹ J
Explanation:
The formula for energy of a photon, E, is:
[tex]E = hf[/tex]
where h is Plank's constant = 6.62 x 10 ⁻³⁴ .
Using the formula:
E = 6.62 x 10⁻³⁴ x 8.34 x 10¹⁴
= 5.52 x 10⁻¹⁹ J
If two balls have the same mass, but ball P is twice as large as ball Q, which one will have the greater density?
a. Ball P
b. ball Q
c. Their densities are equal
a. Ball P
What is density.Density is define as mass per unit volume or the quantity per unit volume, unit area, or unit length.
If [tex]m_{1}[/tex] is mass , [tex]V_{1}[/tex] is volume and [tex]D_{1}[/tex] is density of ball P
[tex]m_{2}[/tex] is mass , [tex]V_{2}[/tex] is volume and [tex]D_{2}[/tex] is density of ball Q
It is given that ,
[tex]V_{1}[/tex] = [tex]V_{2}[/tex];
But [tex]m_{1}[/tex]= [tex]2m_{2}[/tex]
Based on above equation we have:
[tex]\frac{D_{1} }{D_{2} } = (\frac{m_{1} }{V_{1} } )* (\frac{m_{2} }{V_{2} } )\\ \\= (\frac{2m_{2} }{V_{2} })*(\frac{V_{2} }{m_{2} }) \\\\= 2[/tex]
Thus, density of ball P is twice that of Q.
Therefore ,
Ball P will have a greater density than Q
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A 50 g bullet moving horizontally at a velocity of 400 m/s collides and embeds itself in a 25 kg block that rests on a rough horizontal surface and is attached to a spring with a spring constant of 180 N/m. The impact causes a compression of 12 cm in the spring. What is the coefficient of friction between the block and the surface?
The coefficient of friction between the block and the surface is determines as 0.1.
Final velocity of the block and the bulletApply the principle of conservation of linear momentum;
0.05(400) = v(0.05 + 25)
20 = 25.05v
v = 0.8 m/s
Coefficient of frictionApply the principle of conservation of energy
P.E - K.E = Ux
μmgx - ¹/₂mv² = ¹/₂kx²
μ(25.05)(9.8)(0.12) - 0.5(25.05)(0.8)² = 0.5(180)(0.12)
29.459μ - 8.016 = 10.8
29.459μ = 2.784
μ = 0.1
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Lesson 1, What is Physical Science.
Write an expository essay explain the difference between scientific knowledge and other kinds of science, include ideas regarding:
1) the scientific method.
2) true science versus false science.
3) examples of what scientists study and do not study.
4) what is required for a scientist to consider an idea to be true.
Physical science explains the physical world and not supernatural events and an idea is considered true by science if it can be observed, explained and reproduced by others.
What is physical science?
Physical science is a systematic study of the of the physical world and phenomena based on observation and experiments.
The scientific method involves:
observation and questionshypothesisexperimentsresults and further experimentstheories and lawsScience explains the physical world and not supernatural events.
Science studies physical phenomena such as the stars, the planets, living things, etc.
Science do not study about angels or demons or supernatural events.
An idea is considered true by science if it can be observed, explained and reproduced by others.
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An m = 6.11 g bullet is fired into a 365 g block that is initially at rest at the edge of a table of h = 1.08 m height as shown in the figure.
1. The bullet remains in the block, and after the impact the block lands d = 1.84 m from the bottom of the table. How much time does it take the block to reach the ground once it flies off the edge of the table?
2. What is the initial horizontal velocity of the block as it flies off the table?
3. Determine the initial speed of the bullet.
(a) The time taken the block to reach the ground once it flies off the edge of the table is 0.47 s.
(b) The initial horizontal velocity of the block as it flies off the table is 3.91 m/s.
(c) The initial speed of the bullet is 237.5 m/s.
Time of motion of the blockThe time of motion of the block is calculated as follows;
h = ¹/₂gt²
where;
h is height of the tablet is time of motiont = √(2h/g)
t = √( (2 x 1.08) / 9.8)
t = 0.47 s
Initial horizontal velocity of the blockx = vt
v = x/t
v = (1.84)/(0.47)
v = 3.91 m/s
Initial speed of the bulletm1u1 + m2u2 = v(m1 + m2)
where;
m1 is mass of bulletm2 is mass of blocku1 is initial velocity of the bulletu2 is the initial velocity of the blockv is initial horizontal velocity of the block as it flies off the table0.00611(u1) + 0.365(0) = 3.91(0.00611 + 0.365)
0.00611u1 = 1.451
u1 = 1.451/0.00611
u1 = 237.5 m/s
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When passing in a medium for a distance of 1.5 cm intensity
of the light decreased by 3 times. What will the distance x equal to when the intensity of the light decreases by 9 times?
The distance x equal to 0.87 cm when the intensity of the light decreases by 9 times.
Intensity of light
The intensity of light is given as power emitted by the light by unit area.
I = P/A
I = P/L²
I₁L₁² = I₂L₂²
L₂² = I₁L₁²/I₂
L₂² = (3 x 1.5²)/(9)
L₂² = 0.75
L₂ = 0.87 cm
Thus, the distance x equal to 0.87 cm when the intensity of the light decreases by 9 times.
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Suppose astronomers find an earth-like planet that is twice the size of Earth. What must be the mass of this planet such that the gravitational force at the surface would be identical to Earth’s?
This planet's mass must be four times that of Earth in order for the gravitational pull at its surface to be comparable to Earth's.
What is Newton's law of gravitation?Newton's law of gravity states that each particle having mass in the universe attracts each other particle with a force known as the gravitational force.
The gravitational force is proportional to the product of the masses of the two bodies and inversely proportional to the square of their distance.
The planet's mass is directly related to its mass at the surface and inversely proportional to the square of its radius;
When mass increases and distance reduces, gravity rises. Gravity also lowers when the distance between two points grows and the mass decreases.
The astronomers discovered a planet twice the size of Earth that resembles Earth.
This planet's mass must be four times that of Earth in order for the gravitational pull at its surface to be comparable to Earth's.
Hence the masses of this planet will be 4 times that of Earth.
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How many significant digits should the answer to the following problem have? (2.49303 g) * (2.59 g) / (7.492 g) =
The number of significant digits to the answer of the following problem is four.
What are the significant digits?The number of digits rounded to the approximate integer values are called the significant digits.
The following problem is
(2.49303 g) * (2.59 g) / (7.492 g) =
On solving we get
= 0.86184566204
The answer is approximated to 0.86185
Thus, the significant digits must be four.
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How much heat is required to convert 12.0 g of ice at -10.0°C to steam at 100.0°C. Express your answer in joules, calories, and Btu.
what are risk factors of an autoimmune disease
Explanation:
Your Sex. Overall, 78% of people affected by autoimmune disease are female (1). ...Genetics. Certain disorders, such as lupus and multiple sclerosis, tend to run in families (3, 4). ...Having an autoimmune disease. ...Obesity. ...Smoking and Exposure to Toxic Agents. ...Certain Medications. ...Infections.the work function for magnesium is 3.70 ev. what is its cutoff frequency?
The cutoff frequency for magnesium is 8.93 x 10¹⁴ Hz.
What is cutoff frequency?The work function is related to the frequency as
W0 = h x fo
where, fo = cutoff frequency and h is the Planck's constant
Given is the work function for magnesium is 3.70 eV.
fo = 3.7 x 1.6 x 10⁻¹⁹ / 6.626 x 10⁻³⁴
fo = 8.93 x 10¹⁴ Hz.
Thus, the cut off frequency is 8.93 x 10¹⁴ Hz.
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Which is the correct unit for electrical power?
Answer:
As electrical power is measured in Watts (W), therefore it must be also be measured in Joules per Second. So we can correctly say that: 1 watt = 1 joule per second (J/s).
Explanation:
A rocket is fired with an initial Velocity OF 100m/s at an angle OF 55 above the horizontal, It explodes on the mountain Side 12s after its Firing What is x-and y-coordinates of the rocket relative to its Firing point?
Answer:
( 688.29 , 276.66 ) meters
Explanation:
Break into horizontal and vertical components
x = 100 cos 55 = 57.36 m/s
the x coordinate is then 12 seconds * 57.36 m/s = 688.29 meters
y coordinate is a bit more complex because of the curved path due to gravity
Original y velocity = 100 sin 55
y = vo t - 1/2 (9.81)(t^2)
y = 100 sin 55 (12) - 1/2 (9.81) (12)^2
yf = 276.66 meters
A sports car can move 100.0 m in the first 3.8 s of constant acceleration. What is the car's acceleration?
m/s²
The distance covered by an accelerating object starting from rest is
D = (1/2 of acceleration) x (time²).
In this question,
D = 100 m
time = 3.8 s
100 = (1/2 acceleration) x (3.8s²)
100 = (1/2 a) x (14.44)
100/14.44 = 1/2 a
200/14.44 = a
a = 13.85 m/s²
The volume of the water in the graduated cylinder rose as some of the water was displaced by the table tennis ball. Find the volume of the ball using the formula
Vb = Vf – Vi
where Vb is the volume of the ball, Vf is the final volume of the water, and Vi is the initial volume of the water. Record the volume of the ball in Table A of your Student Guide.
What is the volume of the table tennis ball?
cm3
The approximate volume of table tennis ball is 80 cm³
What is volume?Volume is defined as the amount of space occupied by the three dimensional object. S I unit of volume is m³ or cm³.
To find the volume of tennis ball using graduated cylinder.
Step 1 - Fill the graduated cylinder half or full.
Step 2 - Mark the initial volume of the water i.e. 100 cm³ (Vi)
Step 3 - Put the tennis ball in the graduated cylinder. Some of the water was displaced by the table tennis ball.
Step 4 - Mark the Final volume of the water (Vf) i.e. 180 cm³
Step 5 = Calculate the volume by using Formula
Vb = Vf – Vi = 180 cm³ - 100 cm³ = 80 cm³
Hence the volume of tennis ball (Vb) is 80 cm³
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Answer:
40
Explanation:
Object A attracts object B with a gravitational force of 10 newtons from a given distance. If the distance between the two objects is doubled, what is the new force of attraction between them?
Answer:
20 Newtons
Explanation:
10× 2
Answer: A.
2.5 newtons
Explanation: edmentum
If have a custom made telescope with these specifications then what's the focal length of my telescope? (refractor telescope only please)
_Specifications:_
*Objective diameter*: 90mm
*Distance between lenses*: 230mm
*Eyepiece focal length*: 4mm
*Eyepiece size*: 31.7mm
Please respond fast. Also please give a simplified answer for a brainliest answer tag. Thanks!
Answer:
i don't know sorry
i know a good website that may help you
it's called https://skyandtelescope.org/observing/telescope-calculator/
Explanation:
A skater starts from rest v1=0, from the top of an h=6m hill and travels d=20m until it gets to the bottom of the hill where its speed is v2=1.2m/s. If the skater has m=50kg, what is the friction force?
The friction force is 1.5N
skater's initial velocity v1=0height of the hill=20mskater's final velocity=1.2m/sMass of the skater=50kg
Now, using the third equation of motion-
[tex]v^{2}= u^{2} +2as[/tex]
v=final velocity
u=initial velocity
a=acceleration
s=distance
substitute the values in the above equation
1.2=0+ 2a×20
a=1.2/40
a=0.03
friction force=mass ×acceleration
=50×0.03
=1.5N
hence, The friction force is 1.5N
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In a small village in southern Italy, childbirth is considered?
Answer:
a community event
Explanation:
Ross training for a half marathon which is 13.1 miles long. Within four months he has progressed to an 11 mile practice run if Ross takes two months off from training what will likely occur?
If Ross takes two months off from training, his fitness level will reduce in comparison to what it was two months ago.
In as little as 3–4 weeks after beginning strength training, Ross will probably experience weight increase, energy loss, diminished balance, diminished strength (making it tougher to carry out daily tasks), and overall fewer fitness levels.Many people mistakenly believe they lose muscle mass far more quickly than they actually do because their muscles' ability to store water and glycogen is declining.A decrease in strength and muscle mass, with beginners experiencing a smaller decline in strength than experienced lifters.Ross will experience Increased VO2 Max from exercise. VO2 Max is almost completely lost in people who train at lower intensities.learn more about fitness here: https://brainly.com/question/13490156
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Your heart pumps about 70 mL of blood per beat and beats an average of 80 Times per minute how many gallons of blood does your heart pump every hour
Answer:
88.761
Explanation:
state two factors that affect current carrying capacity of an accumulator
The two factors that affect current carrying capacity of an accumulator will be accumulator size and ambient temperature
What is the function of the accumulator?Utilizing the compressible and decompressible properties of nitrogen gas, an accumulation vessel is used to store hydraulic pressure.
These key deciding elements are:
1. Accumulator Size: The current capacity increases as the circumference of the conductor increases.
2. Ambient Temperature: The greater the ambient temperature, the less heat is needed to raise the insulation's maximum operating temperature.
3. Accumulator identification:
4. Conditions for Installation:
Hence, the two factors that affect current carrying capacity of an accumulator will be accumulator size and ambient temperature
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3
012 10.0 points
A car with mass 1060 kg crashes into a wall.
The car's velocity immediately before the col-
lision was 14.6 m/s and the bumper is com-
pressed like a spring with spring constant
1.14 × 107 N/m.
What is the maximum deformation of the
bumper for this collision?
Answer in units of m.
013 10
Hi there!
The maximum deformation of the bumper will occur when the car is temporarily at rest after the collision. We can use the work-energy theorem to solve.
Initially, we only have kinetic energy:
[tex]KE = \frac{1}{2}mv^2[/tex]
KE = Kinetic Energy (J)
m = mass (1060 kg)
v = velocity (14.6 m/s)
Once the car is at rest and the bumper is deformed to the maximum, we only have spring-potential energy:
[tex]U_s = \frac{1}{2}kx^2[/tex]
k = Spring Constant (1.14 × 10⁷ N/m)
x = compressed distance of bumper (? m)
Since energy is conserved:
[tex]E_I = E_f\\\\KE = U_s\\\\\frac{1}{2}mv^2 = \frac{1}{2}kx^2[/tex]
We can simplify and solve for 'x'.
[tex]mv^2 = kx^2\\\\x = \sqrt{\frac{mv^2}{k}}[/tex]
Plug in the givens and solve.
[tex]x = \sqrt{\frac{(1060)(14.6^2)}{(1.14*10^7)}} = \boxed{0.0198 m}[/tex]
