Answer:
More energy is transferred in situation A
Explanation:
Each of the situations are analyzed as follows;
Situation A
The temperature of the cup of hot chocolate = 40 °C
The temperature of the interior of the freezer in which the chocolate is placed = -20 °C
We note that at 0°C, the water in the chocolate freezes
The energy transferred by the chocolate to the freezer before freezing is given approximately as follows;
E₁ = m×c₁×ΔT₁
Where;
m = The mass of the chocolate
c₁ = The specific heat capacity of water = 4.184 kJ/(kg·K)
ΔT₁ = The change in temperature from 40 °C to 0°C
Therefore, we have;
E₁ = m×4.184×(40 - 0) = 167.360·m kJ
The heat the coffee gives to turn to ice is given as follows;
E₂ = m·[tex]H_f[/tex]
Where;
[tex]H_f[/tex] = The latent heat of fusion = 334 kJ/kg
∴ E₂ = m × 334 kJ/kg = 334·m kJ
The heat required to cool the frozen ice to -20 °C is given as follows;
E₃ = m·c₂·ΔT₂
Where;
c₂ = The specific heat capacity of ice = 2.108 kJ/(kg·K)
Therefore, we have;
E₃ = m × 2.108 ×(0 - (-20)) = 42.16
E₃ = 42.16·m kJ/(kg·K)
The total heat transferred = (167.360 + 334 + 42.16)·m kJ/(kg·K) = 543.52·m kJ/(kg·K)
Situation B
The temperature of the cup of hot chocolate = 90 °C
The temperature of the room in which the chocolate is placed = 25 °C
The heat transferred by the hot cup of coffee, E, is given as follows;
E = m×4.184×(90 - 25) = 271.96
∴ E = 271.96 kJ/(kg·K)
Therefore, the total heat transferred in situation A is approximately twice the heat transferred in situation B and is therefore more than the heat transferred in situation B
Energy transferred in situation A = 543.52 kJ/(kg·K)
Energy transferred in situation B = 271.96 kJ/(kg·K)
Energy transferred in situation A ≈ 2 × Energy transferred in situation B
∴ Energy transferred in situation A > Energy transferred in situation B.
How much gravitational potential energy has a boy whose mass is 50 kg and
who is standing on top of a 2.5 meter high wall?
a. none of these
b. 0735 j
c. 2115 j
d. 196
Answer:
Gravitational potential=mgh
=50×10×2.5
=1250J
option a
R=70
R-40
M
120V
R, 90
W
Answer:
please type full question. Does not mean what you are trying to saying.Of all the mutations, we can conclude that one mutation would MOST LIKELY contribute to a rapid rate of
extinction. That is
Answer:
A) blindness
Explanation:
A current of 0.225 A flows across an 85.5 Ohm resistor. How much voltage is being applied?
Answer:
19.24 volts
Explanation:
From Ohm's law,
Applying,
V = IR.................. Equation 1
Where V = Voltage applied, I = currentflowing across the resistor, R = Resistance
From the question,
Given: I = 0.225 A, R = 85.5 Ohm
Substitute these values into equation 1
V = (0.225×85.5)
V = 19.24 volts
Hence the Voltage applied is 19.24 Volt
Answer:
19.24
Explanation:
acellus
A magnetic material would always be what to a magnet
Answer:
attractive/magnetic
mark me brainliestt :))
what does it mean to "conserve money" or to "conserve resources"
Answer:
Conserve money means to save money. Conserve resources means the same thing but with resources; so conserve resources means to save resources.
Explanation:
The value of gravitational pull on the moon is 1.6 m/s/s. What is the weight of a 75 kg
astronaut on the moon?
Answer:
120N
Explanation:
Weight=mass x acceleration due to gravity (on the planet)
Mass of an astronaut is 75kg and value of acceleration due to gravity on moon is 1.6m/s2
Weight of astronaut on moon=mass of astronaut x value of acceleration due to gravity on moon
75kg x 1.6m/s2
=120N
Two trains each of length 100m are running on two parallel trucks .One train overtakes the other in 20s and one train crosses the other in 10s.Calculate the velocity of each train
Answer:
The velocity of one of the trains is 15 m/s
The velocity of the other train 5 m/s
Explanation:
The given parameters of the two trains and the motion of the trains are;
The length of each train, l = 100 m
The time it takes one train to overtake the other, Δt₁ = 20 s
The time it takes the one train to cross the other, Δt₂ = 10 s
Let 'v₁' represent the velocity of one of the trains, and let 'v₂' represent the velocity of the other train, we have;
When one train overtakes the other, the trains are moving in the same direction and the relative velocity of the overtaking train, v = v₁ - v₂
The distance the train travels when overtaking or crossing, d = 2 × l
∴ d = 2 × 100 m = 200 m
d = 200 m
Therefore, we get;
v = v₁ - v₂ = d/Δt₁ = (200 m)/(20 s) = 10 m/s
∴ v₁ - v₂ = 10 m/s [tex]{}[/tex] Equation (1)
When one train crosses the other train, the trains are moving in opposite directions on the different tracks, therefore, we have;
For the overtaking trains, v = v₁ + v₂ = d/Δt₂ = (200 m)/(10 s) = 20 m/s
∴ v₁ + v₂ = 20 m/s [tex]{}[/tex] Equation (2)
Adding equation (1) to equation (2) gives;
v₁ - v₂ + v₁ + v₂ = 2·v₁ = 10 m/s + 20 m/s = 30 m/s
∴ v₁ = 30 m/s/2 = 15 m/s
The velocity of one of the trains, v₁ = 15 m/s
From equation (2), we have;
v₁ + v₂ = 20 m/s
v₂ = 20 m/s - v₁
∴ v₂ = 20m/s - 15 m/s = 5 m/s
The velocity of the other train, v₂ = 5 m/s.
Explain why air is not used as a
brake fluid
Answer:
A gas is not used in hydraulic machines as the fluid because gas is easily compressible and so if a gas is used, the energy would mostly go into compressing a gas. Therefore a liquid is used in hydraulic machines as the fluid.
Explanation:
I got you bro:)
Who discovered natural magnet for the first time?
The ratio of carbon-14 to nitrogen-14 in an artifact is 1:7. Given that the half-
life of carbon-14 is 5730 years, how old is the artifact?
A. 5730 years
B. 22,920 years
C. 11,460 years
D. 17,190 years
Answer:
17,190 years old
Explanation:
D
how do scientist check repeatability of results
Answer:
If research results can be replicated, it means they are more likely to be correct.
Answer: There are many things that have to be checked in order to know
Explanation:
For repeatability to be established, the following conditions must be in place: the same location; the same measurement procedure; the same observer; the same measuring instrument, used under the same conditions; and repetition over a short period of time.
Hope this helps!
Pls Mark me brainliest
A baseball player hits a 140 g baseball with a force of 2800 N. What is the
acceleration of the ball as it leaves the bat?
A. 0.050 m/s2
B. 20 m/s2
C. 390 m/s2
D. 20,000 m/s2
What do wind energy, hydro-energy, and fossil fuel energy have in common?
Answer:
Fossil fuels store energy from the sun as
Explanation:
Match each concept to the scientist who supported it.
Thomas Young
Light is a wave that has similar properties
as radio waves
Christiaan Huygens
Light is a wave made of electric and
magnetic fields.
James Clerk Maxwell
Light is a wave because this property can
explain interference.
Heinrich Hertz
Light is a wave because it bends when it
hits barriers and openings.
Isaac Newton
Light is made of particles because it travels
only in straight paths.
Answer:
1. Heinrich Hertz.
2. James Clerk Maxwell.
3. Thomas Young.
4. Christiaan Huygens.
5. Isaac Newton.
Explanation:
Light wave can be defined as an electromagnetic wave that do not require a medium of propagation for it to travel through a vacuum of space where no particles exist.
However, the various definitions of light according to early scientists include the following;
1. Heinrich Hertz: Light is a wave that has similar properties as radio waves. Heinrich Rudolf Hertz was a German physicist born on the 22nd of February, 1857 in Hamburg, Germany. The unit of frequency ("Hertz") of an electromagnetic wave was named after him.
2. James Clerk Maxwell: Light is a wave made of electric and magnetic fields. James Clerk Maxwell was a Scottish physicist born on the 13th of June, 1831 in Edinburgh, United Kingdom. He was famously known for his work in the formulation of the classical theory of electromagnetic radiation.
3. Thomas Young: Light is a wave because this property can explain interference.
4. Christiaan Huygens: Light is a wave because it bends when it hits barriers and openings.
5. Isaac Newton: Light is made of particles because it travels only in straight paths.
Answer:
See image
Explanation:
Light wave can be defined as an electromagnetic wave that do not require a medium of propagation for it to travel through a vacuum of space where no particles exist.
However, the various definitions of light according to early scientists include the following;
1. Heinrich Hertz: Light is a wave that has similar properties as radio waves. Heinrich Rudolf Hertz was a German physicist born on the 22nd of February, 1857 in Hamburg, Germany. The unit of frequency ("Hertz") of an electromagnetic wave was named after him.
2. James Clerk Maxwell: Light is a wave made of electric and magnetic fields. James Clerk Maxwell was a Scottish physicist born on the 13th of June, 1831 in Edinburgh, United Kingdom. He was famously known for his work in the formulation of the classical theory of electromagnetic radiation.
3. Thomas Young: Light is a wave because this property can explain interference.
4. Christiaan Huygens: Light is a wave because it bends when it hits barriers and openings.
5. Isaac Newton: Light is made of particles because it travels only in straight paths.
How can you stay safe on the Internet?
A. Create a screen name that includes your first and last name.
B. Do not talk to people you know online.
C. Do not share any personal information.
D. Share your parents' information.
Answer:
I believe the answer is C.
Explanation: Hope this helps and have a great day! :)
What is electrical resistance and types of electrical resistance
Answer:
Electrical Resistance is a measure of the opposition to current flow in an electrical circuit
Types: variable resistance and set resistance
Explanation:
I need help
With this
Answer:
dfvgxbcjnhmv,kbl
Explanation:
fvgbnhjmk
True or false: balanced forces are important for a hoverboard to float.
True
False
Answer:
True its got to be true
Explanation:
how else does a hoverboard float lol
Answer:
It's true
Explanation:
So true..
1 7 points If you take less time to perform a task, you have less power output. O True O False
True
The rate at which work is done is referred to as power. A task done quite quickly is described as having a relatively large power. The same task that is done more slowly is described as being of less power. Both tasks require he same amount of work but they have a different power.
5. How do you represent the strength of a force in a free-body diagram?
A student practicing for a track meet ran 250 m in 30 sec
Answer:
v= 8.3 m/ s^-1
Explanation:
S=vt
v= S/t
v= 250 m/ 30 s
v= 8.3 m/ s^-1
A student on an amusement park ride moves in circular path with a radius of 3.5 m once every 4.5 s. What is the tangential velocity of the student?
Answer:
the tangential velocity of the student is 4.89 m/s.
Explanation:
Given;
the radius of the circular path, r = 3.5 m
duration of the motion, t = 4.5 s
let the student's tangential velocity = v
The tangential velocity of the student is calculated as follows;
[tex]v = \frac{2\pi r}{t} \\\\v = \frac{2 \pi \times 3.5}{4.5} \\\\v = 4.89 \ m/s[/tex]
Therefore, the tangential velocity of the student is 4.89 m/s.
Where is an object's center of gravity?
The center of gravity (CG) location is the average location of all the weights of an object. The center of gravity is the balance point of an object, also expressed as the point where all the mass appears to be located.
The location of the body's center of gravity is where its mass is concentrated. The human body's center of gravity is a fictitious position where the gravitational force is claimed to appear to act (COG). It is where the body's overall bulk seems to be concentrated.
What is an object's center of gravity?The center of gravity of an object is the point at which its weight is most evenly distributed. Any object's travel through space may be completely explained in terms of how its center of gravity moves from one location to another and, if it is free to spin, how it rotates around that center of gravity.
Therefore, In physics, the center of gravity is a hypothetical location within a solid where, for the sake of convenience in some computations, the body's whole weight may be assumed to be concentrated.
Learn more about center of gravity here:
https://brainly.com/question/17409320
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PLSSSSS HELPPPPP HELPPPPP
When did whale ancestors begin living full time in the water?
a.
After they nursed under water
b.
After they lost their hind legs
c.
Before they evolved gills
d.
Before they began eating a carnivorous
diet
Question 1 (1 point)
All solid objects will deform when enough force is applied.
O True
False
Answer:
Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to plasticity, in which the object fails to do so and instead remains in its deformed state.
Explanation:
Answer:
It is false
Explanation:
because when it like a rolling ball it can deform no matter what unlesss you throw it at the ground really hard then it breaks but a soft or sometimes metal yeah it can deform but not all things solid deform.
Two Brothers are playing soccer on the beach. One brother kicks the ball really hard and the ball lands in the water, about 50 meters from the beach. They wonder if the ball will float back to the beach.
Answer:
Due to wind and waves of water.
Explanation:
They wonder that the ball will float back to the beach because of the wind and the waves of the water. The wind blows towards the beach which moves the water in the form of waves towards the beach so if the ball lands in the water, it will floats on the surface of water and move towards the beach with the help of wind and waves of the sea. The ball floats on the water due to its lighter weight and lower density as compared to water.
10
5 points
What is the power of a small motor that can do 2500 J of work in 25 seconds?
0.01 Watts
100 Watts
1000 Watts
62500 Watts
Answer:
100 Watts
Explanation:
Energy can be defined as the ability (capacity) to do work.
Given the following data;
Energy = 2500 J
Time = 25 seconds
To find the power of the motor;
Power = energy/time
Substituting into the formula, we have;
Power = 2500/25
Power = 100 Watts
4. When a key on piano is pressed, a sound is heard. What produces this sound?
A. the vibrating key of the piano
B.
The Vibrating String Of Piano
C. the finger pressing the piano key
D. the air molecules inside the piano
Answer:
D
Explanation:
since we press the key , air molecules ate presented and sound wave is formed what we hear.
Answer:
B
Explanation:
the vibrating string of pianoThe SI unit for pressure is the
Answer:
The SI unit of pressure is Pascal .