Answer:
answer is E
Explanation:
iv. An object is 14 cm in front of a convex mirror. The image is 5.8 cm behind the mirror. What is the focal length of the mirror? A. 4.1cm B. 8.2 cm C. 9.9 cm D. 20 cm
Answer:
C. 9.9 cm
Explanation:
The location of the object, u = 14 cm
The location of the image, v = 5.8 cm
The focal length of the mirror, f = Required
The mirror formula for a convex mirror is given as follows;
[tex]\dfrac{1}{u} -\dfrac{1}{v} = -\dfrac{1}{f}[/tex]
Therefore, we get;
[tex]\dfrac{1}{14 \ cm} -\dfrac{1}{5.8 \ cm} =- \dfrac{41}{406 \ cm} = -\dfrac{1}{f}[/tex]
Therefore;
[tex]f = \dfrac{406 \ cm}{41} \approx 9.9 \ cm[/tex]
The focal length of the mirror, f ≈ 9.9 cm
TRUE OR FALSE. when an object changed direction without changing its speed, it is not accelerating
Answer:
True.
Explanation:
The velocity vector is constant in magnitude but changing in direction. Because the speed is constant for such a motion, many students have the misconception that there is no acceleration. ... But the fact is that an accelerating object is an object that is changing its velocity.
The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing
Answer:
Nuclear fusion in the Sun's core causes the release of tremendous amounts of energy that leads to very high temperatures and pressure which is much hotter and higher than the temperature and pressure at the exterior surface of the Sun causing the particles in the inner core region to push outwards towards the Sun's surface
Explanation:
When an apple falls towards the earth, the earth moves up to meet the apple . Is this true ? If yes . Why is the earth's motion not noticeable.
To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least:
Answer:
To explore the other planets, the satellite must have the velocity more than the escape velocity.
Explanation:
The minimum velocity required by any object to escape from the earth gravitational pull is called the escape velocity.
The escape velocity for any planet depends on the mass of planet and radius of planet. It does not depends on the mass of object. The escape velocity is same for any mass for a particular planet.
So, to explore the other planets, the satellite must have the velocity more than the escape velocity.
Astronomers observe the Small Magellanic Cloud (SMC), a not very dense, rather small galaxy near us. They notice that even those stars that formed recently have relatively few heavier elements (when compared to such recent stars in our Milky Way.) What is the likely explanation for this deficiency
Answer:
The reason it has few heavier elements is due to the fact that it's stars are widely spaced and this implies that it's stars have very low rate of formation and termination.
Explanation:
The Small Magellanic Cloud, is basically a very tiny galaxy located near the Milky Way. Although it's tiny, it's diameter is approximately 7,000 light-years while it also contains over hundred million stars which are widely spaced.
Now, the reason it has few heavier elements is due to the fact that it's stars are widely spaced and this implies that it's stars have very low rate of formation and termination.
A uniform meter rule of mass 10g is balanced on a knife edge placed at 45cm mark. Calculate the distance of a mass 25g from the pivot
Answer:
2 cm.
Explanation:
Please see attached photo for diagram.
In the attached photo, y is the distance from the pivot to which the 25 g is placed.
The value of y can be obtained as follow:
Clockwise moment = 5 × 10
Anticlock wise moment = y × 25
Anticlock wise moment = Clockwise moment
y × 25 = 5 × 10
y × 25 = 50
Divide both side by 25
y = 50/25
y = 2 cm
Thus, the distance is 2 cm
Mean diameter of cylinder measured by A is 2.50 cm with a possible error of 0.25 cm whereas mean height of cylinder measured by B is 10.0 cm with a possible error of 0.5 cm. Whose measurement is more accurate?
Answer:
The measurement of first cylinder is more accurate.(A)
Explanation:
The least possible error higher will be accuracy.
Using atomic weight crystal structure and atomic radius data tabulated inside the front cover compute the theoritical densities of alminuim ,nikel......
Question
Using atomic weight, crystal structure, and atomic radius data tabulated inside the front cover of thebook, compute the theoretical densities of aluminum (Al), nickel (Ni), magnesium (Mg), and tungsten (W), and thencompare these values with the measured densities listed in this same table. The c/a ratio for magnesium is 1.624.
Explanation:
Which statement or question is a good hypothesis
explain the role of standard units to bring uniformity in the measurement
Answer:
We need standard unit for measurement to make our judgement more reliable and accurate. For proper dealing, measurement should be same for everybody. Thus there should be uniformity in measurement. For the sake of uniformity we need a common set of units of measurement, which are called standard units.
Which of these would have the greatest pressure?
Group of answer choices
A large balloon with few gas molecules at a high temperature
A small balloon with many gas molecules at a low temperature
A small balloon with many gas molecules at a high temperature
A large balloon with few gas molecules at a low temperature
In uplifting 750 newton load with the help of 2 meter long lever lever took 250 newton efforts . What will be the efficiency of a machine if the fulcrum is kept 50 cm from the load
Answer:
the efficiency of the machine is 100%
Explanation:
Given;
load, L = 750 N
length of the lever, L = 2 m
effort applied, E = 250 N
Position of the load from the fulcrum, = 50 cm
50cm
0↓--------------------------Δ-------------------------------↓---------200 cm
750 N x cm 250 N
Apply the principle of moment;
750(50) = 250(x)
x = (750 x 50) / (250)
x = 150 cm
the distance of the effort = 150 cm = 1.5 m
the distance of the load = 50 cm = 0.5 m
The velocity ratio of the machine = 1.5/0.5
= 3
The mechanical advantage of the machine is calculated as;
M.A = Load/effort
M.A = 750 / 250
M.A = 3
The efficiency of the machine is calculated as;
E = (M.A / V.R) x 100%
E = (3/3) x 100% = 100%
Therefore, the efficiency of the machine is 100%
A ball is dropped from a roof of a building and strikes the ground in 3 seconds. If a second ball is thrown horizontally from the roof, it will hit the ground in:
it will hit the ground maybe in like 1 second I guess
Which of the following is an example of a surface wave?
A. Compression wave
B. Sound wave
C. Electromagnetic wave
D. Ocean wave
Answer:
ocean wave
hope it helped you
What happens in a series circuit when more bulbs are added? (Example: I start out with a complete series circuit with 2 bulbs. Then I add in several more wires and several more bulbs & bulb holders. Now I have a complete series circuit with 5 bulbs).
Answer:
when we add elements in a series circuit the voltage across each element decreases
Explanation:
In a series circuit the current the whole circuit is the same, since there is only one path,
resistance is the sum of the resistance of each element
R_{eq} = ∑ R_i
if we write ohm's law
V = i R_{eq}
we substitute
V = i ∑ R_i
therefore the total voltage is
V = ∑ i R_i = ∑ V_i
With this expression we see that the voltage decreases as we place more elements in the series circuit.
Specifically when we fear two elements the voltage across each element is
V_i = V / 2
when we have 5 elements the voltage across each element is
V_i = V / 5
therefore when we add elements in a series circuit the voltage across each element decreases
A piano string of density 0.0050 kg/m is under a tension of 1,350 N. Find the velocity with which a wave travels on the string.
Answer:
519.62 m/s
Explanation:
Applying,
v = √(T/m').............. Equation 1
Where v = velocity of the wave, T = Tension on the string, m' = mass per unit length of the string
From the question,
Given: T = 1350 N, m' = 0.005 kg/m
Substitute these values into equation 1
v = √(1350/0.005)
v = √(270000)
v = 519.62 m/s
A 0.15-mm-wide slit is illuminated by light of wavelength 462 nm. Consider a point P on a viewing screen on which the diffraction pattern of the slit is viewed; the point is at 26.9° from the central axis of the slit. What is the phase difference between the Huygens' wavelets arriving at P from the top and midpoint of the slit?
Answer:
[tex]\triangle \phi=461.5rad[/tex]
Explanation:
From the question we are told that:
Silt width [tex]w=0.15=>0.1510^{-3}[/tex]
Wavelength [tex]\lambda=462nm=462*10^{-9}[/tex]
Angle [tex]\theta=26.9[/tex]
Generally the equation for Phase difference is mathematically given by
[tex]\triangle \phi=\frac{2 \pi}{\lambda}(\frac{wsin\theta }{2})[/tex]
[tex]\triangle \phi=\frac{2 \pi}{462*10^{-9}}(\frac{0.1510^{-3}*sin 26.9 }{2})[/tex]
[tex]\triangle \phi=461.5rad[/tex]
[tex]\triangle \phi=146.89\pi[/tex]
If displacement has a magnitude AND direction is it a scalar or vector quantity?
scalar
vector
Explanation:
Obviously vector quantity
3.00 m^3 of water is at 20.0°C.
If you raise its temperature to
60.0°C, by how much will its
volume expand?
Water
ß = 207•10-6C-1
(Unit = m^3)
Answer:
9m^3
Explanation:
Given data
volume v1= 3m^3
volume v2= ???
Temperature T1= 20.0°C.
Temperature T2= 60.0°C.
Applying the relation for temperature and volume
V1/T1= V2/T2
substitute
3/20= V2/60
3*60= V2*20
180= 20*V2
180/20= V2
V2= 9m^3
Hence the final volume is 9m^3
In the diagram, q1 = +2.00 x 10-5 C,
q2 = +3.80 x 10-6 C, and q3 = +5.30 x 10-5 C.
What is the electric potential energy, Ue, for
charge qy? Include the correct sign (+ or -).
Answer:
U = 3.59 10⁻⁹ J
Explanation:
Electric potential energy is
U = k ∑ [tex]\frac{q_iq_j }{r_i_j}[/tex]
in this case
U = k (q₁q₂ / r₁₂ + q₁q₃ / r₁₃ + q₂q₃ / r₂₃)
the distances are
r₁₂ = 1.15
r₁₃ = 1.15 +2.88 = 4.03 m
r₂₃23 = 2.88
we substitute
U = 9 109 (2 10-5 3.8 10-6 / 1.15 + 2 10-5 5.30 10-5 / 4.03 + 3.8010-6 53 010-5 / 2.88)
U = 9 109 (6.609 10-11 + 2.63 10-10 + 6.99 10-11)
U = 9 109 (39,899 10-11)
U = 3.59 10⁻⁹ J
Answer:
Q2 = 0.0346 J
Explanation:
I don't know what Q1 is but I did solve for Q2. I'm using this because no other question has been asked to solve for Q2 :)
Rick works off commission. He earns 10 percent of all manufacturing equipment he sells. if he made a sale of $9,000 how much was his commission
Answer:
$900
Explanation:
Step 1: Our output value is 9000.
Step 2: We represent the unknown value with x.
Step 3: From step 1 above,$9000=100\%$
Step 4: Similarly, x=10%
Step 5: This results in a pair of simple equations:
$9000=100
Step 6: By dividing equation 1 by equation 2 and noting that both the RHS (right hand side) of both
equations have the same unit (%); we have
\frac{9000}{x}=\frac{100\%}{10\%}
Step 7: Again, the reciprocal of both sides gives
\frac{x}{9000}=\frac{10}{100}$
\Rightarrow x=900$
Therefore, $10\%$ of $9000$ is $900$
unknown value with x
step 1 above,$9900=100%
similarly ,x=10%
1) Convert the following:
I) 65 kg into g
ii) 87570 seconds into hour
iii) 7.5 km into m
Answer:
65000g
24.325 hrs
7500m
Answer:
I) 65000 g II)24.325 hours III)7500 m
Explanation:
I) 1 kg = 1000 g
65 kg = 65 * 1000 g = 65000 g
II) 1 hour = 3600 seconds
1 second = 1/3600 hours
87570 seconds = 87570 * 1/3600 hours =24.325 hours
III) 1 km = 1000 m
7.5 km = 7.5 * 1000 m = 7500 m
An acceptable radiograph was taken using 40 mAs at 80 kVp at a distance of 60 inches. A second radiograph is requested at 40 inches. What mAs should be used to produce this radiograph with a 40-inch distance
Answer:
17.8 mAs
Explanation:
The exposure maintenance formula shows that as SID increases, intensity decreases, causing a decrease in film exposure and density. The mAs is directly proportional to the square of the distance. That is as mAs increases, distance increases, and vice versa, in order to maintain image receptor exposure. It is given by:
[tex]\frac{mAs_1}{mAs_2}=\frac{D_1^2}{D_2^2}[/tex]
Given that mAs₁ = original mAs = 40 mAs, D₁ original distance = 60 in, D₂ = new distance = 40 in, mAs₂ = new mAs
[tex]\frac{mAs_1}{mAs_2}=\frac{D_1^2}{D_2^2}\\\\mAs_2=\frac{mAs_1*D_2^2}{D_1^2}=\frac{40*40^2}{60^2}=17.8\\\\mAs_2=17.8\ mAs[/tex]
Do you believe in aliens? And if so, what's your reasoning for believing in them?
Answer:
I believe in aliens but I do not think everyone should. I started to believe in aliens since the US government said they would be taking extraterrestrial life seriously. They will be in our lives sooner or later, so we shouldn't be ignoring their presence. I believe them because surveys show that nearly half of Americans believe that aliens have visited the Earth, either in the ancient past or recently. That percentage has been increasing. Belief in alien visitation is greater than belief that Bigfoot is a real creature, but less than belief that places can be haunted by spirits. Also there have been a lot of UFO sightings, and a Navy Jet has a video of that as well. These small things is just hard to ignore, and they make me and hopefully others believe in aliens.
Two identical metallic sphere having unequal opposite charges are are placed
distance of 0.05m apart in air.
After bringing them in contact
with each other, they are again placed at the same distance apart, now the force of repulsion between them is 0.108 N. Calculate the final charge on each of them.
Answer:
Let the initial charges be q1 and q2 respectively.
After they come in contact, the charges are rearranged such that they acquire same charge.
let us say that charge on each of them is Q.
They are again brought apart at a distance of 0.9 m. Hence, the force between them will be given as
F = kQ2 / r2
0.025 = (9×109 x Q2) / 0.92
Q2 = 0.025 x 0.92 / 9×109
Q = 1.5 x 10-6 C
Explanation:
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Name One formula that uses joules
Answer:
[tex]{ \bf{power \: { \tt{(watts)}} = \frac{workdone \: { \tt{(joules)}}}{time \: { \tt{(seconds)}}} \: }}[/tex]
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26. D. crushing the sugar cube and dissolving it in water.
27. A. atom
28. B. molecule
29. B. plum pudding model of Joseph John Thomson
30. B. He used cathode ray tubes which showed that all atoms contain tiny negatively charged subatomic particles or electrons
31. D. protons and neutrons are relatively heavier than electrons.
Physicist Max Planck showed how objects like stars give off different colors based on their temperature. What color are the hottest stars
Answer:
the brightest found are Blue - White with
Explanation:
The energy emission of objects increases with their temperature, specifically Wien described the process in an expression
[tex]\lambda_{maximum}[/tex] T = 2,898 10⁻³
With this expression we can find the temperature of the stars by the color they emit.
Specifically the Sun has a color of 550 nm which corresponds to 5400K
bright stars have a BLUE color corresponding to 7500K
the brightest found are Blue - White with a temperature of 20000K
What does the sun use for nuclear fusion?
Answer:
The sun uses hydrogen for nuclear fusion.
Answer:
Hydrogen
Explanation:
