Answer:
yes, the density of ice is less than the density of water. Ice floats on water.
Explanation:
why a magnetic compass is used to determine the direction.
Answer:
the magnetic compass is used to determine direction because it is one of the most accurate form of magnet as we already know that a freely suspended magnet always faces towards north direction and south direction
A man stands still on a moving walkway that is going at a speed of 0.2 m/s to
the west. What is the velocity of the man according to a stationary observer?
A. 0.2 m/s north
B. 0.2 m/s west
C. 0.2 m/s South
D. 0.2 m/s east
When,a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west,then the velocity of the man according to a stationary observer would be 0.2 m/s west,Therefore, the correct answer would be option B.
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. The velocity of an object is depend on the magnitude as well as the direction of the object.
the mathematical expression for velocity is given by
velocity = total displacement /time
The speed and velocity of the object are very different from each other because speed does not depend upon the direction of the moving object but velocity depends on the magnitude of speed as well as the direction of the moving object.
As per given in the problem a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west therefore from the perspective of a stationary observer the velocity of man would be 0.2 m/s towards West.
Hence the correct options for the problem would be option B.
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TUOI 7. A stone dropped from a window reaches the ground in 1.5 seconds. Calculate the height of the window above the ground
The height of the window above the ground is 11.025m
The first step is to write out the parameters given in the question
U(initial velocity)= 0
Time= 1.5 seconds
Acceleration due to gravity= 9.8
Therefore the height of the window can be calculated as follows
S= ut + 1/2gt²
= 0(1.5) + 1/2(9.8)(1.5²)
= 0 + 1/2(9.8)(2.25)
= 1/2(22.05)
= 0.5×22.05
= 11.025
Hence the height of the window above the ground is 11.025m
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Which two statements are true about a system?
a)A system is a group of objects analyzed as one unit.
b)Energy that moves across system boundaries is conserved.
c)There’s only one way to define the boundaries of a system.
d)All systems are made by humans.
The energy required to change the state of a substance was determined to be E(H).
If the mass of the substance was DOUBLED, the value of E(H) will
(A) be halved
(B) be doubled
(C) be quadrupled
(D) remain constant
Answer:
ccccccccc or bbbbbbb or aaaaaaaa or ddddddd
The moon Phobos orbits Mars
(mass = 6.42 x 1023 kg) at
a distance
of 9.38 x 106 m. What is its period of
orbit?
[?]s
Answer:
Explanation:
We are basically needing to solve for the time in the equation d = rt, where d is the distance around Mars (aka the circumference), r is the velocity, and t is time. We need to find the circumference and the velocity. We will begin with the velocity.
Because the gravitational attraction between Phobos and Mars provides the centripetal acceleration necessary to keep Phobos in its (sort of) circular path, the equation we use for this is:
[tex]F_g=F_c[/tex] which says that Force supplied by gravity is equal to the centripetal force. Expanding that:
[tex]\frac{Gm_{Phobos}m_{Mars}}{r^2}=\frac{m_{Phobos}v^2}{r}[/tex]
When we move that around mathematically to solve for the velocity value, what we end up with is:
[tex]v=\sqrt{\frac{Gm_{Mars}}{r}[/tex] and filling in:
[tex]v=\sqrt{\frac{(6.67*10^{-11})(6.42*10^{23})}{9.38*10^6} }[/tex] and we get that
v = 2100 m/s
Now for the circumference:
C = 2πr and
C = 2(3.1415)(9.38 × 10⁶) so
C = 5.9 × 10⁷
Putting that all together in the C = vT equation:
5.9 × 10⁷ = 2100T so
T = 2.8 × 10⁴ sec or 7.8 hours
If the wave is detected 12.5 minutes after the earthquake, estimate the distance from the detector to the site of the quake
Answer:
Remember the relation:
Speed*Time = Distance.
We can estimate that the speed at which an earthquake "moves", in the surface, is:
S = 6km/s (this is a low estimation actually)
Then if the wave is detected 12.5 minutes after the earthquake, we know that it traveled for 12.5 minutes before reaching the detector.
So we know the speed of the wave and the time it took to reach the detector, then we can use the equation:
Speed*Time = Distance.
to find the distance.
First, we should write the time in seconds
we know that:
1 min = 60 s
then:
12.5 min = 12.5*(60 s) = 750 s
Then, the wave traveled with a speed of 6 km/s for 750 seconds until it reached the detector, then the distance that it traveled is:
(6km/s)*750s = 4500 km
The distance between the detector and the site of the quake is around 4500 km.
If the box of 500N is placed over the land of area of 2m²,what pressure is experted by the box on the land?
Answer:
250 Pa or N/m^2
Explanation:
Pressure(P)=F/A=500/2=250 Pa or N/m^2
The mass of an object is 4G and it has a density of 5gm^-3. what is the volume
Explanation:
Density is mass in grams over volume in cubic centimeters.
So it is
[tex]\frac{4g}{5cm^{-3} }[/tex] = 0.8 g/cm[tex]^{3}[/tex]
The unit is grams per cubic centimeter.
NB - density can also be kilograms over cubic meters
HELP ME
Which two changes to the can opener would increase its mechanical efficiency?
A shorten the paddle so that they are closer in size to the axle that they turn
B grease the rotating wheel of the opener so that there is less breaks in between moving parts
C replaced it with a straight handle the act as levers with shorter pieces of metal
D sand the cutting surface of the metal piece so that it is perfectly smooth and sharp
Answer:
I THINK IT'S D....
HOPE SO
what is volum?Write its SI unit.write the si unit mass and length.
Explanation:
Volume is the quantity of three-dimensional space enclosed by a closed surface
The si unit of mass is kilogram (kg) and the si unit of length is metre(m)
Which direction do electrons travel
A.from negative to positive
B.in either direction depending on the circuit
C.from positive to negative
D.they don’t move they simply exchange charge
Answer:
option a negative to positive
Explanation:
The flow of electrons is termed electron current. Electrons flow from the negative terminal to the positive. Conventional current or simply current, behaves as if positive charge carriers cause current flow. Conventional current flows from the positive terminal to the negative
brainliest plsss
A bullet of mass of 50g is moving with the velocity of 200km/h .calculate the kinetic energy of the bullet .
Answer:
is 10³
Explanation:
cuz the formula of KE is 1/2mv²
covert 50g to kg first then plug in the formula
1/2 × 0.05 × 200 = 10³ J
1. How much heat energy ( Q ) is required to heat 2.0 kg of copper from 30.0 oC to 80.0 oC?
Answer:
38500
Explanation:
I looked it up so it may be wrong
when an apple falls towards the earth the earth moves up to meet the apple. Is it true? If yes, why is the earth motion not noticeable ?
Answer:
Yes, this is true.
-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.
-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.
-- The mass of the Earth is about 5.972 x 10²⁴ kg.
-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.
-- That's why you don't notice the Earth's motion.
-- Also, you're standing on the Earth, moving up with it, toward the apple. Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.
Answer From Gauth Math
in what condition does a body float
Answer:
if buoyant force is equal is equal to the weight of body then our body float. if density of our body is less than density of liqiud then our body float in water.
the weight of a body is 420 newton.calculate it's mass
Answer:
42g
Explanation:
the mass of a body is given by
m=weight/gravity
=420/10
=42
I hope this helps
what will happen to the gravitational force between two bodies if the distance between them is halved keeping their masses constant ?..
Which is an example of current electricity?
Answer:
D
Explanation:
i just did it trust me
(This is for other people with this Question i hope you find this when you need help) Need answer for this Help!!!
Question 7 of 20 You plan to use a slingshot to launch a ball that has a mass of 0.025 kg. You want the ball to accelerate straight toward your target at 19 m/s2. How much force do you need to apply to the ball? O A. 19.03 N OB. 0.48 N O C. 4.51 N D. 760.00 N
Answer:
0.48N
Explanation:
according to the second law of motion
force=mass×acceleration
the mass in this question is 0.025,the acceleration 19
therefore f=0.025×19
=0.48N
I hope this helps
Una onda se propaga en un medio P, de tal forma que recorre una distancia 8D en un tiempo 4T. La misma onda cuando se propaga por un medio Q recorre una distancia 4D en el mismo tiempo anterior, es decir, en 4T. Respecto a esta onda es correcto afirmar que *
Sabemos todo material tiene asociado un coeficiente de difracción n.
De tal forma que la velocidad de una onda electromagnetica que viaja a travez de dicho material, será:
v = c/n
donde c es la velocidad de la luz.
Con la información dada, podremos concluir que el coeficiente de difracción del medio Q es dos veces el del medio P.
Ahora veamos como llegamos a esto:
Sabemos que en el medio P, la onda recorre una distancia 8*D en un tiempo 4*T
entonces la velocidad de la onda en el medio P es:
[tex]V_p = \frac{8*D}{4*T} = 2*\frac{D}{T}[/tex]
Mientras que en el medio Q, recorre una distancia 4*D en un tiempo 4*T, por lo que la velocidad en el medio Q será:
[tex]V_Q = \frac{4*D}{4*T} = \frac{D}{T}[/tex]
Podemos ver que:
[tex]V_P = 2*V_Q[/tex]
Reescribiendo las velocidades como el cociente entre la velocidad de la luz y el correspondiente coeficiente de difracción obtenemos:
[tex]\frac{c}{n_P} = 2*\frac{c}{n_Q} \\\\n_Q = 2*n_P[/tex]
Es decir, podemos concluir que el coeficiente de difracción del medio Q es dos veces el del medio P.
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b. The role of the moon is greater than that of the sun in the occurrence of tides. ???
Our sun is 27 million times larger than our moon. Based on its mass, the sun's gravitational attraction to the Earth is more than 177 times greater than that of the moon to the Earth. If tidal forces were based solely on comparative masses, the sun should have a tide-generating force that is 27 million times greater than that of the moon. However, the sun is 390 times further from the Earth than is the moon. Thus, its tide-generating force is reduced by 3903, or about 59 million times less than the moon. Because of these conditions, the sun’s tide-generating force is about half that of the moon.
Define electric current and drift velocity.
Answer:
Current- the flow of free charges, such as electrons and ions
Drift velocity- the average speed at which these charges move
Answer:
An electric current is the stream of changed particals, such as electrons & ions, moving through an electrical conductor.
The average velocity attained bycharged partical ,such as electrons,in a material due to electric fields
Momentum is a quantity that we say is typically _______________ in collisions.
A. Conserved
B. Lost
C. Disappeared
D. Gained
Momentum is a quantity that we can say is typically conserved in collisions.
Momentum is the quantity that that we see typically conserve in the collision,therefore the correct answer is the option A
It is the type of collision in which the total momentum as well as the kinetic energy on the system is conserved .The momentum before the collision is equal to the momentum after the collision in other words one can say in the elastic collision momentum of the quantity is conserved.
In the inelastic collision the momentum is conserved but the kinetic energy of the quantity is not conserved.
Momentum of a quantity is conserved irrespective of the type of collision whether it will be elastic collision or inelastic collision the momentum of the quantity will always be conserved.
Hence,we can say that momentum is the quantity that is conserved in collision,The correct answer for the given problem is option A.
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A sample of Radon-222 has a half-life of 3.82 days. After 11.46 days, there is 5 grams of Radon-222 remaining. How much Radon-222 was in the original sample?
30 grams
2 grams
15 grams
40 grams
Como surgiu a capoeira?
HELP!!
A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
When the apple fall towards tje earth tje earth move up to meet the apple.Os it true.If yes why is the earth motion not noticeable
Answer:
Explanation:
It was Newton's genius that saw that it was true. He also realized that if it was true, the motion the earth experience would be unmeasurably small, especially in his time. Their instruments were just not good enough: crude and too approximate would be better descriptions.
(A) A triangular glass prism of thickness 12cm is placed on a mark on a piece of paper resting on a horizontal bench. If the refractive index of the material of the prism is 1.5, calculate the apparent displacement of the mark.
(B)Water is poured into a jar to a depth of 24cm. The bottom of the jar appears
to be raised by 6cm when viewed vertically. Calculate the refractive index of water.
Part A - The apparent displacement of the mark is 4 cm.
The refractive index of a material, n = real depth, D/apparent depth, L.
So, n = D/L
Since the refractive index of the triangular glass prism is 1.5, n = 1.5. Also, the triangular glass prism is 12 cm thick and placed on a mark on a piece of paper resting on a horizontal bench. So, the real depth of the mark on the piece of paper through the triangular prism is D = 12 cm and its apparent depth is L.
Since n = D/L,
making L, subject of the formula, we have
L = D/n
Substituting the values of the variables into the equation, we have
L = D/n
L = 12 cm/1.5
L = 8 cm
so, the apparent depth of the mark is 8 cm.
So, the apparent displacement of the mark is d = D - L = 12 cm - 8 cm = 4 cm
Thus the apparent displacement of the mark is 4 cm.
Part B - The refractive index of water, n = 1.33.
The refractive index of a material, n = real depth, D/apparent depth, L.
So, n = D/L
Since the depth of water in the jar is 24 cm, the real depth, D = 24 cm.
Also, the bottom of the jar appears to be raised by 6 cm. So, the apparent depth, L = 24 cm - 6 cm = 18 cm
Since n = D/L, the refractive index of water n = D/L
Substituting the values of the variables into the equation, we have
n = D/L
= 24 cm/18 cm
= 1.33
So, the refractive index of water, n = 1.33.
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I need help asap please
Answer:
I dont know answer Sorry For that thank u
