Answer:
O
Explanation:
Matters exist majorly either as solids, liquids or gases. These are called states of matter. A change of state occurs when a substance either absorb or release energy.
Since the atoms of the substance lost energy and become close together with the ability to slide past one another, the change of state is from gaseous to liquid. And the process is called condensation (O). Thus the process is that of O, called condensation.
Answer:
O
Explanation:
your welcome have a great day.
A heat pump operates on a Carnot heat pump cycle with a COP of 8.7. It keeps a space at 248C by consum-ing 2.15 kW of power. Determine the temperature of the reservoir from which the heat is absorbed and the heat-ing load provided by the heat pump.
Answer:
Heat of the reservoir is 461.38 K or 188.1 °C
The heating load is 18.705 kW
Explanation:
COP = 8.7
working temperature [tex]T_{h}[/tex] = 248 °C = 248 + 273.3 = 521.3 K
work power W = 2.15 kW
reservoir temperature [tex]T_{c}[/tex] = ?
heating load Q = ?
We know that
COP = Q/W
Q = COP x W = 8.7 x 2.15 = 18.705 kW
Also,
COP = [tex]\frac{T_{h} }{T_{h}- T_{c} }[/tex] = [tex]\frac{521.3}{521.3- T_{c} }[/tex]
8.7 = [tex]\frac{521.3}{521.3- T_{c} }[/tex]
4535.31 - 8.7[tex]T_{c}[/tex] = 521.3
4535.31 - 521.3 = 8.7[tex]T_{c}[/tex]
4014.01 = 8.7[tex]T_{c}[/tex]
[tex]T_{c}[/tex] = 4014.01/8.7 = 461.38 K
or 461.38 -273.3 = 188.1 °C
A man can walk three blocks east and four blocks north in 20 min. He can drive 12 times that distance in the same amount of time. How far can the man
drive in 20 min? Assume that each block is 0.3 kilometers.
Answer: 25.2 km
Explanation:
3 blocks east and four blocks east = 7 blocks
1 block = 0.3 km --> 7 blocks = 2.1 km
12 times 2.1 km = 25.2 km
A body is thrown vertically upward and the height travelled by it is 200m , find the initial velocity and time required to reach maximum height ?
Answer:
Initial velocity(u)=62.6 m/s^2Time(t)=6.39 secondsSolution,
Displacement(s)=200 m
Initial velocity (u)=?
Final velocity(v)=0 m/s^2
acceleration due to gravity(g)=-9.8 m/s^2
now,
[tex] {v}^{2} = {u}^{2} + 2as \\ {(0)}^{2} = {u}^{2} + 2 \times ( - 9.8) \times 200 \\ {u}^{2} = 2 \times 9.8 \times 200 \\ {u}^{2} = 3920 \\ u = \sqrt{3920} \\ u = \sqrt{ {62.6}^{2} } \\ u = 62.6 \: metre \: per \: second[/tex]
Again,
Finding time taken,
[tex]v = u + at \\ t = \frac{v - u}{a} \\ = \frac{0 - 62.6}{ - 9.8} \\ = \frac{ - 62.6}{ - 9.8} \\ = 6.39 \: seconds[/tex]
Hope this helps...
Good luck on your assignment...
. What happens to the polarity of an electromagnet when the direction of the current passing through it is reversed?
Answer:
The polarity of electromagnet also gets reversed when the direction of current is reversed. The current flows from negative terminal to positive terminal in an electromagnet due to the flow of electrons so polarity is also established in the electromagnet. As, the current direction is reversed, the polarity of magnet also gets reversed because the polarity of magnet depends on the direction of the current.
A man weighing 80kg is standing on a trolley weighing
320kg. The trolley resting on smooth horizontal rails. If
the man starts walking on the trolley along the rails with
a speed of 1ms", then his displacement relative to the
ground after 4 second is
1) 4.8 m 2) 4 m 3) 3.2 m 4) 2.8 m
Answer:
Net displacement = 3.2 m
Explanation:
Given:
Mass of man = 80 kg
Mass of trolley = 320 kg
Speed = 1 m/s
Time = 4 sec
Computation:
Displacement by man = 1 m/s × 4 sec
Displacement by man = 4 m
Net ext force (trolley) = com at rest
So,
320 × X = 80(4 - X)
32X = 32 - 8X
40X = 32
X = 0.8 m
Net displacement = 4 m - 0.8 m
Net displacement = 3.2 m
Answer:
3) 3.2 m
Explanation:
The computation of the displacement relative to the ground after 4 seconds is shown below:
Let us assume the following
Starting x coordinate is at the origin
As it does not involve any external force so x coordinated would remain unchanged
Now the separation between the man and the trolley is
[tex]= 4 \times 1[/tex]
= 4 m
And, we assume the displacement of man be x
So, for trolley it would be (4 -x)
Now we develop the equation which is
[tex]80 \times x = 320 \times (4 - x)[/tex]
x = 16 - 4x
Therefore x = 3.2 m
1. How much heat energy is required to raise the temperature of a 5 kg aluminium bar
from 28°C to 68°C ?
( Specific heat capacity of aluminium = 900 J kg C)
Answer:
180 kJ
Explanation:
Given that:
Mass (m) = 5 kg
Initial temperature (T1) = 28°C
Final temperature (T2) = 68°C
The change in temperature (ΔT) = T2 - T1 = 68°C - 28°C = 40°C
Specific heat capacity of aluminium (c) = 900 J/kg°C
The quantity of heat energy required (q) is given by:
q = mcΔT
q = 5 kg × 900 J/kg°C × 40°C
q = 180000 Joules
q = 180 kJ
Therefore 180 kJ is required to raise the temperature of aluminium from 28°C to 68°C.
A gas occupies a volume of 1.0 m3 in a cylinder at a pressure of 120kPa. A piston compresses the gas until the volume is 0.25m3, the temperature remaining constant. What is the new pressure of the gas?
Answer:
Approximately [tex]480\; \rm kPa[/tex], assuming that this gas is an ideal gas.
Explanation:
Let [tex]V(\text{Initial})[/tex] and [tex]P(\text{Initial})[/tex] denote the volume and pressure of this gas before the compression. Let [tex]V(\text{Final})[/tex] and [tex]P(\text{Final})[/tex] denote the volume and pressure of this gas after the compression.By Boyle's Law, the pressure of a sealed ideal gas at constant temperature will be inversely proportional to its volume. Assume that this gas is ideal. By this ideal gas law:
[tex]\displaystyle \frac{P(\text{Final})}{P(\text{Initial})} = \frac{V(\text{Initial})}{V(\text{Final})}[/tex].
Note that in Boyle's Law, [tex]P[/tex] is inversely proportional to [tex]V[/tex]. Therefore, on the two sides of this equation, "final" and "initial" are on different sides of the fraction bar.
For this particular question:
[tex]V(\text{initial}) = 1.0\; \rm m^3[/tex].[tex]P(\text{Initial}) = 120\; \rm kPa[/tex].[tex]V(\text{final}) = 0.25\; \rm m^3[/tex].The pressure after compression, [tex]P(\text{Final})[/tex], needs to be found.Rearrange the equation to obtain:
[tex]\displaystyle P(\text{Final}) = \frac{V(\text{Initial})}{V(\text{Final})} \cdot P(\text{Initial})[/tex].
Before doing any calculation, think whether the pressure of this gas will go up or down. Since the gas is compressed, collisions between its particles and the container will become more frequent. Hence, the pressure of this gas should increase.
[tex]\begin{aligned}P(\text{Final}) &= \frac{V(\text{Initial})}{V(\text{Final})} \cdot P(\text{Initial})\\ &= \frac{1.0\; \rm m^{3}}{0.25\; \rm m^{3}} \times 120\; \rm kPa = 480\; \rm kPa\end{aligned}[/tex].
[03.02]
In order to change power, what else must be changed? (1 point)
Answer:
Current or voltage should also be changed.
Explanation:
Please i need a Brainliest.
Determine the amount of time for polonium-210 to decay to one fourth its original quantity. The half-life of polonium-210 is 138 days. Explain.
Answer:
276 days
Explanation:
1/4 th of the original means 2 half lives
1 half life = 138 days
So,
2 half lives = 276 days
a body starts from rest and gains the velocity of 5 metre per second into second is it of uniform velocity explain
Answer:
It is not a uniform velocity, because his velocity increases for 5 m every second (acceleration = 5m/s2), meaning his velocity always changes.
When he starts at rest, his velocity is 0 m/s. But in 1 second later, his velocity is already 5m/s. At 2 seconds, his velocity will be 10 m/s.
I NEED HELP PLEASE, THANKS! :)
Generate an explanation for the following formula: P = I²R . Explain.
Answer:
P = VI = (IR)I = I2R
Explanation:
What the equation means is that if you double the current you end up with 4 times the power loss. It's like the area of carpet you need for a room - if you make the room twice as long and twice as wide you need 4x as much carpet. The physical explanation is that the voltage difference along a wire depends on the current - more current flowing with a resistance means more voltage (pressure of electricity if you like) is built up.
This extra voltage means more power. So if you double the current your would double the power, but you also double the voltage which doubles the power again = 4x as much power. P = VI = (IR)I = I2R
I hope this helps you out, if I'm wrong, just tell me.
As I mentioned earlier, Ohm's law gives us the formula P = IV, where V is the voltage ( also known as the electrical potential difference ) and I is the current. It is confusing that P = I²R and P = IV are one in the same - so I want to go a bit deeper on that.
We have three formulas, P = IV, P = I²R, and P = V² / R. Each are considered the same. The two formulas P = I²R, and P = V² / R are derived from the statement that P = IV, under the condition V = IR. Substitute the value of V from this second condition V = IR into P = IV. You would get the following -
P = I( IR ),
P = I²R
That is how one can derive the formula P = I²R, and how P = IV and P = I²R are thought to be one in the same. If you would like, take a look at how to get the formula " P = V² / R, "
V = IR, P = IV
I = V / R, P = IV
P = ( V / R )V,
P = V² / R
Hope that helps!
if spiderman runs and jumps horizontally from the top of a 200m high building, what does he need his velocity to be to land on a building 100m high, 10m away from him?
Answer:
v = 2.22 m/s
Explanation:
First we apply the second equation of motion to the vertical motion of the body:
s = Vi t + (1/2)gt²
where,
s = y = vertical distance covered = 200 m - 100 m = 100 m
Vi = V₀y = Vertical Component of Initial Velocity = 0 m/s (because spider man jumps horizontally, thus his velocity has no vertical component initially)
t = Time Taken to Land on 100 m high building = ?
g = 9.8 m/s²
Therefore,
100 m = (0 m/s)t + (0.5)(9.8 m/s²)t²
t² = (100 m)/(4.9 m/s²)
t = √(20.4 s²)
t = 4.5 s
Now, we analyze the horizontal motion. Neglecting air friction, the horizontal motion is uniform with uniform velocity. Therefore,
s = vt
where,
s = x = horizontal distance covered = 10 m
v = V₀ₓ = Horizontal Component of Initial Velocity = Initial Velocity = ?
Therefore,
10 m = v(4.5 s)
v = 10 m/4.5 s
v = 2.22 m/s
Do action and reaction act on the same
body or on different bodies?
plochlain
answer with Khe help of bocample. How Core
they related in magnitude and direction?
Explanation:
action and reaction forces act on the same body since these are forces that oppose that are opposite
Q- A body is acted upon by two forces 30N due east and 40N due North. Calculate
resultant and its direction.
Answer:
the following image will make you understand
Explanation:
The weight of the buggy was 40 N on Mars. When the buggy landed on Mars it rested on an area of 0.025 m2.Calculate the pressure exerted by the buggy on the surface of Mars. Give the unit.
Answer:
P = 1600 W
Explanation:
The weight of the buggy on Mars is 40 N.
It landed on area of 0.025 m^2.
Pressure is given as force per unit area:
P = F / A
where F = force
A = area
Weight is a force, therefore, the pressure exerted by the buggy on that surface of Mars is:
P = 40 / 0.025
P = 1600 W
The count rate of a radioactive source decreases from 1600 counts per minute to 400 counts per minute in 12 hours. What is the half-life of the source?
Answer:
[tex]t_{1/2}=6 h[/tex]
Explanation:
Let's use the decay equation.
[tex]A=A_{0}e^{-\lambda t}[/tex]
Where:
A is the activity at t timeA₀ is the initial activityλ is the decay constantWe know that [tex]\lambda=\frac{ln(2)}{t_{1/2}}[/tex]
So we have:
[tex]\lambda=\frac{ln(A/A_{0})}{t}[/tex]
[tex]\frac{ln(2)}{t_{1/2}}=\frac{ln(A/A_{0})}{t}[/tex]
[tex]t_{1/2}=\frac{t*ln(2)}{ln(A/A_{0})}[/tex]
[tex]t_{1/2}=6 h[/tex]
Therefore, the half-life of the source is 6 hours.
I hope it helps you!
Suppose that a driver applies a force of 140 N to the master cylinder, which has a diameter equal to 14 the diameter of the brake cylinder. What is the force applied by the brake cylinder on the brake shoe?
Answer:
force on brake shoes is 10 N
Explanation:
for the master cylinder;
force applied = 140 N
diameter = 14d
for brake cylinder;
force applied on the brake shoe by the brake cylinder f = ?
diameter = d
The pressure will be transmitted undiminished from the master cylinder to the brake cylinder according to pascals pressure law.
pressure = force/area
but cross sectional area is proportional to diameter of the cylinder
therefore
[tex]\frac{140}{14d } = \frac{f}{d }[/tex]
the diameters will cancel out, and we're left with
force on brake shoes = 10 N
how to calculate displacement
Un resorte se alarga 5 cm bajo la acción de una fuerza de 39,2 N. ¿Cuál es la constante del resorte? Si ahora la fuerza es 68,6 N. ¿Cuál es el nuevo alargamiento?
Answer:
[tex]k=784 N/m[/tex]
[tex]\Delta x=8,8 cm[/tex]
Explanation:
Usando la ley de Hook tenemos:
[tex]F=k\Delta x[/tex]
Solving it for k we have:
[tex]k=\frac{F}{\Delta x}[/tex]
[tex]k=\frac{39,2}{0,05}[/tex]
[tex]k=784 N/m[/tex]
Usando la misma ecuación y sabiendo k tenemos:
[tex]\Delta x=\frac{F}{k}[/tex]
[tex]\Delta x=\frac{68,6}{784}[/tex]
[tex]\Delta x=8,8 cm[/tex]
Espero esto te ayude!
How is mercury barometer constructed ?
Answer:
A mercury barometer is a device use to measure stomspheric pressure and is constructed as following:
A mercury barometer requires a tube which has one close end, and one open end.Tube is placed upside down in a beaker in such a way so that one end open in the beaker and the other remain outside of the beaker. The barometric liquid (mercury) is then filled in the tube by pouring mercury liquid in the beaker.The position of tube creates vacuum between the closed end of the tube and liquid surface and the Mercury has high density that is why used as the liquid to measure pressure.
Newton’s third law of motion says that for every action there is a(n) and opposite reaction.
Answer:
for every action thete is an equal and opposite reaction
Answer:
Newton’s third law of motion says that for every action there is a(n)
equal and opposite reaction.
Explanation:
just got it right edg 1928
A 0.3-m-radius automobile tire rotates how many revolutions after starting from rest and accelerating at a constant 2.13 rad/s2 over a 23.2-s interval?
Answer:
The automobile tire rotates 91 revolutions
Explanation:
Given;
angular acceleration of the automobile, α = 2.13 rad/s²
time interval, t = 23.2-s
To calculate the number of revolutions, we apply the first kinematic equation;
[tex]\theta = \omega_i \ + \frac{1}{2} \alpha t^2[/tex]
the initial angular velocity is zero,
[tex]\theta =0\ + \frac{1}{2} (2.13) (23.2)^2\\\\\theta = 573.2256 \ Rad[/tex]
Find how many revolutions that are in 573.2256 Rad
[tex]N = \frac{\theta}{2 \pi} = \frac{573.2256}{2\pi} \\\\N = 91 \ revolutions[/tex]
Therefore, the automobile tire rotates 91 revolutions
A baboon steals an apple and runs to a nearby boulder 10.0\,\text m10.0m10, point, 0, start text, m, end text to its left. The baboon reaches the boulder in 1.0\,\text s1.0s1, point, 0, start text, s, end text with a constant acceleration of 20.0\,\dfrac{\text m}{\text s^2}20.0 s 2 m 20, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, squared, end fraction leftward. What was the baboon's initial velocity when it started running to the boulder?
Given that,
Distance = 10 m
Time = 1.0 sec
Acceleration a =20 m/s²
We need to calculate the baboon's initial velocity
Using equation of motion
[tex]s=ut+\dfrac{1}{2}at^2[/tex]
Where, s = distance
t = time
a = acceleration
Put the value in to the formula
[tex]10=u\times1+\dfrac{1}{2}\times20\times1^2[/tex]
[tex]u=10-10[/tex]
[tex]u=0\ m/s[/tex]
Hence, The baboon's initial velocity is zero.
What does the use of the phrase "the lucky ones"
convey about the author's viewpoint?
What does the phrase "But we never ate enough to
satisfy our hunger" demonstrate about the author?
Answer:
1. He feels worse off.
2. His awareness of the grim situation.
Explanation:
Elie Weisel's memoir "Night" is about the persecution of the jews by the Germans during the worst genocide in world history. The events leading up to the Holocaust and the resulting after-effects through his personal experience provides one of the most prominent witness accounts of the crime.
When Weisel states that "lying down wasn't an option", he reveals how congested space was in the cabin. The "lucky ones" were able to breathe in the fresh air from the window, while the rest have to be satisfied with wherever they are. This reveals his realization of the grim situation inside the over-packed cabin, where there is hardly any space to move.
And when he said that they "never ate enough to satisfy our hunger", he presents the realization and understanding of the grim situation in the train's cabin where eating is not a luxury, but a necessity to stay alive. And for that, they know they have to "economize, to save for tomorrow" rather than just stay full once.
Answer:
1. He feels worse off.
2. His awareness of the grim situation.
Explanation:
A car starts from rest, then accelerates at 1.20 m/s^2 for 7.00 s. It hits the brakes, slowing to stop at a rate of -4.25 m/s^2. What is the total time for the problem? (Unit = s) PLEASE HELP!!
Answer:
8.98 secsExplanation:
First part of the journey;
If the car starts from rest, then accelerates at 1.20 m/s^2 for 7.00 s, the total time taken during this period is 7.0s.
But then lets get the velocity v of the car during its first part of the journey.
Using the formula v1 = u1+ at1
v = 0+1.2(7)
v = 8.4m/s
Second part of the journey is when the driver hits the brake and slowing to stop at a rate of -4.25 m/s^2. To calculate the time it takes by the body to decelerates, we will use the equation of motion v2 = u2 + at2
v = final velocity of the car during the second part of the journey
u = initial velocity of the car during the second part of the journey
a = deceleration
t = time taken
Given v2 = 0m/s, u2 = 8.4m/s, a = -4.25m/s²
0 = 8.4-4.25t2
4.25t2 = 8.4
t2 = 8.4/4.25
t2 = 1.98secs
Total time taken for the journey = t1+t2
= 7.0s + 1.98s
= 8.98secs
Which of these is an example of overcoming static friction?
A. Speeding up on a bike
B. Starting to pedal a bike that is stationary
C. Slowing down on a bike
D. Trying to stop a bike while pedaling
Answer:
Option B. is the best choice.
Explanation:
Static friction is a force that keeps an object at rest. It must be overcome to start moving the object. Once an object is in motion, it experiences kinetic friction.
B. Starting to pedal a bike that is stationary
Best Regards!
Answer:
I think that the answer is option B)
Explanation:
Plzz answer this questions
will mark as brainlist
Answer:
1. 19.28 secs
2. 154.22 m
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 16 m/s
Final velocity (v) = 0
Force (F) = 1000 N
Mass (m) = 1200 Kg
Time (t) =..?
Distance (s) =...?
Next, we shall determine the acceleration of the car. This can be obtained as follow:
Force (F) = 1000 N
Mass (m) = 1200 Kg
Acceleration (a) =.?
Force (F) = mass (m) x acceleration (a)
F = ma
1000 = 1200 x a
Divide both side by 1200
a = 1000/1200
a = 0.83 m/s²
Since the car is coming to rest, it means it is decelerating. Therefore, the acceleration is – 0.83 m/s²
1. Determination of time taken for the car to halt i.e stop. This can be obtained as follow:
Initial velocity (u) = 16 m/s
Final velocity (v) = 0
acceleration (a) = – 0.83 m/s²
Time (t) =.?
v = u + at
0 = 16 + (–0.83 x t)
0 = 16 – 0.83t
Rearrange
0.83t = 16
Divide both side by 0.83
t = 16/0.83
t = 19.28 secs.
Therefore, the time taken for the car to halt is 19.28 secs.
2. Determination of the distance travelled by the car before coming to rest. This can be obtained as follow:
Initial velocity (u) = 16 m/s
Final velocity (v) = 0
acceleration (a) = – 0.83 m/s²
Distance (s) =..?
v² = u² + 2as
0 = 16² + (2 x –0.83 x s)
0 = 256 – 1.66s
Rearrange
1.66s = 256
Divide both side by 1.66
s = 256/1.66
s = 154.22 m
Therefore, the distance travelled by the car before coming to rest is 154.22 m.
Holiday lights are often connected in series and use special lamps that short out when the potential difference across a lamp increases to the line voltage. Generate an explanation why and explain why these light sets might blow their fuses after many bulbs have failed.
Answer:
If there isn't this type of mechanism, the whole setup will blow even if only one lamp burns out. Doing this mechanism is to decrease the overall resistance resulting in an increased current (Since resistance and current are inversely related) which is the best to blast the fuse.
A train starting from rest picks up a speed of 20 m/s in 20 s while travelling on a straight path. It continues to move at the same speed for the next 50 s. It is then brought to rest in the next 10 s.
a. Plot the speed-time graph for the train..
e. How much distance did the train cover during this entire journey?
Answer:
[tex]1300 m[/tex]
Explanation:
As the path is straight, so the speed is equivalent to velocity. Now. assuming that the acceleration and deceleration of the train are constant. So, change of velocity with respect to time for acceleration as well as deceleration is constant. Hence, the slope of the speed-time graph is constant for the time of acceleration as well as deceleration. The speed for the time from [tex]20 s[/tex] to [tex]70 s[/tex] is constant, so slope for this interval of time is zero. The speed-time graph is shown in the figure.
The total distance covered by the train during the entire journey is the area of the speed-time graph.
Area[tex]=\frac{1}{2}(20\times 20)+ 50\times 20+\frac{1}{2}(20\times 10)[/tex]
[tex]=200+1000+100[/tex]
[tex]=1300[/tex]
As velocity is in [tex]m/s[/tex] and time is in [tex]s[/tex] so the unit of area is [tex]m[/tex]
Hence, the total distance is [tex]1300m[/tex].
In this graph, what is the displacement of the particle in the last teo seconds?
A. 0.2 meters
B. 2 meters
C. 4 meters
D. 6 meters
Answer: B
Explanation:
Displacement is a vector quantity. it is the distance covered in a specific direction.
Whereas, Velocity = displacement/time
Make displacement the subject of formula
Displacement = velocity × time
From the graph, velocity is constant which is equal to 1 m/s
Displacement in the last two seconds will be velocity multiply by 2. Since time = 2s. Therefore,
Displacement = 1 × 2 = 2 m
So, the particle displacement in the last two seconds will be 2 metres