Answer:
110.25 watt/s
Explanation:
The rate of heat transfer is given by the formula
R = k*A(T1 - T2) / d, where
k = thermal conductivity, 0.105 (W/(m*K)
d = thickness, 4 mm = 0.004 m
T1 = inside temperature, 25° C
T2 = outside temperatures, -10° C
A = area 0.3 * 0.4 = 0.12 m²
Now, applying the given data to the formula, we have
Rate = 0.105 * 0.12 (25 - -10) / 0.004
Rate = 0.105 * 0.12(35) / 0.004
Rate = 0.105 * 4.2 / 0.004
Rate = 0.441 / 0.004
Rate = 110.25 Watt/s
Therefore, the steady state rate of heat flow is 110.25 watt/s
A 2.80 kg mass is dropped from a height of 4.50 m. Find its potential energy when it reaches the ground.
Answer:
123.48J
Explanation:
Given parameters:
Mass of the ball = 2.8kg
Height = 4.5m
Unknown:
Potential energy = ?
Solution:
The potential energy is the energy due to the position of a body. It is mathematically given as;
P.E = mgh
m is the mass
g is the acceleration due to gravity
h is the height
Now insert the parameters and solve;
P.E = 2.8 x 4.5 x 9.8 = 123.48J
Answer:
0
Explanation:
There is 0 PE when its on the ground
10. A boy weighs 475 N. What is his mass? (acceleration due to gravity on Earth is 9.8m/s2 = g)
Answer: mass = 48.47 kg.
Explanation:
Formula : Weight = mg , where m = mass of body , g= acceleration due to gravity .
Given: Weight = 475 N
[tex]g= 9.8\ m/s^2[/tex]
Substitute all values in formula , we get
[tex]475= m \times9.8\\\\\Rightarrow\ m = \dfrac{475}{9.8}\\\\\Rightarrow\ m \approx 48.47\ kg[/tex]
Hence, his mass = 48.47 kg.
Can I get help on this question please
it would be the 3rd one. so C
g A wave on a string has a speed of 13.3 m/s and a period of 0.3 s. What is the frequency of the wave
Answer:
3.33 Hz
Explanation:
The first step is to calculate the wavelength
= speed × period
= 13.3 × 0.3
= 3.99
Therefore the frequency of the wave can be calculated as follows
= speed/wavelength
= 13.3/3.99
= 3.33 Hz
A book is sitting on a table. Which of the following is true about the table?
Answer:
Its pulling down on the book
Explanation: if it was pushing up the book would be floating and the other choices don't make sense
two spheres A and B are projected off the edge of a 1.0 m high table with the same horizontal velocity . sphere A has a mass of 20.g and sphere B has a mass of 10.g.
If both spheres leave the edge of the table at the same instant, sphere A will land
a. at some time after sphere B.
b. at the same time as sphere B.
c. at some time before sphere B.
d. There is not enough information to decide.
Answer:
c. because A will land first becuase its heavier
Explanation:
During an experiment, Ellie records a measurement of 25,000 m. How would she write her
measurement in scientific notation?
O 2.5 x 10^2 m
O 2.5 x 10^3 m
0 2.5 x 10^5 m
O 2.5 x 10^4.m
Answer:
D. 2.5 x 10^4
Explanation:
10 to the power of 4 is 10,000.
10,000 x 2.5 = 25,000
D. 2.5 x 10⁴ is the scientific notation of Ellie records.
What is scientific notation?Scientific Notation is the expression of a number n in the form a∗10ᵇ. where a is an integer such that 1≤|a|<10. and b is an integer too. It is a way of writing very large or very small numbers. A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10.
According to the question,
The given number is 25,000 m
i.e.
25 x 10³
Since we have to put the decimal between 2 and 5
It becomes,
2.5 x 10⁴
or
10 to the power of 4 is 10,000.
10,000 x 2.5 = 25,000
Therefore,
The answer is 2.25 x 10⁻⁶ M
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Help me please..
When the slope of a velocity vs. time graph is negative and constant,
what type of motion is occurring?
A) No motion
B) Constant speed
C) Acceleration
D) Constant Velocity
E) Going in circles
a cyclist accelerates at a rate of 7.0 m/s2. how long will it take the cyclist to go from a velocity of 4 m/s to a velocity of 18 m/s?
Answer:
2.57 seconds (rounded to 2.6 Seconds)
Step-by-step explanation:
Great question, it is always good to ask away and get rid of any doubts that you may be having.
Before we can solve this question we need to create a formula that calculates the final speed. The formula will be the following,
Where:
Vf is the final Velocity
Vi is the initial velocity
A is the acceleration
t is the time in seconds
Now that we have the formula we can plug in the values given to us in the question and solve for the amount of time (t).
Finally, we can see that it would take the cyclist 2.57 seconds (approximately) to reach a speed of 18 m/s
I hope this answered your question. If you have any more questions feel free to ask away at Brainly.
Putting the selected answers in parenthesis
A cation has a (Negative, Positive, Neutral) charge, because they have (Lost, Maintained, Gained) electrons. An anion has a (Negative, Positive, Neutral) charge, because they have (Lost, Maintained, Gained) electrons. An atom with the same number and protons and neutrons have a (Negative, Positive, Neutral) charge.
Answer:
gimmie
Explanation:
Two clear but non-mixing liquids each of depth 15 cm are placed together in a glass container. The liquids have refractive indices of 1.75 and 1.33. What is the apparent depth of the combination when viewed from above?
Answer:
The apparent depth d = 19.8495 cm
Explanation:
The equation for apparent depth can be expressed as:
[tex]d = \dfrac{d_1} {\mu_1}+\dfrac {d_2}{\mu_2}[/tex]
here;
[tex]d_1 = d_2 = 15 \ cm[/tex]
[tex]\mu_1[/tex] = refractive index in the first liquid = 1.75
[tex]\mu_2[/tex] = refractive index in the second liqquid= 1.33
∴
[tex]d = \dfrac{15}{1.75}+\dfrac{15}{1.33}[/tex]
[tex]d = 15( \dfrac{1}{1.75}+\dfrac{1}{1.33})[/tex]
[tex]d = 15( 0.5714 +0.7519)[/tex]
d = 15(1.3233 ) cm
d = 19.8495 cm
Which statement describes an example of static electricity?
A. When a light switch is flipped, electrons flow to a lightbulb.
B. Wind turns a generator, causing electrons to flow into power lines.
C. Electrons move from one end of a copper wire to another.
D. Positively and negatively charged particles are attracted to each other.
The answer is Positively and negatively charged particles are attracted to each other.
The amplitude of a pendulum is doubled. This means:
a
the pendulum will have twice its original mass.
b
the frequency of the pendulum will be twice as high.
c
the pendulum will swing twice as far away from the center.
d
the period of the pendulum will be twice as long.
Answer:
the period of the pendulum will be twice as long.
Explanation:
because i looked it up
A car of mass 1200 kg travels at a steady dpeed of 22 m/s around a bend of radius 50 m. Find the centripetal force required?
Compute the magnitude of the centripetal acceleration a :
a = (22 m/s)² / (50 m) = 9.68 m/s²
Then the magnitude of the centripetal force is
F = (1200 kg) (9.68 m/s²) = 11,616 N ≈ 12,000 N
The truck needs 11,616 N of centripetal force to bend around a radius 50 m.
From the centripetal acceleration,
[tex]a = \dfrac{v^2}{r}[/tex]
Where,
[tex]a[/tex]- Centripetal acceleration
[tex]v[/tex]- velocity = 22 m/s
[tex]r[/tex]- radius = 50 m
Put the values,
[tex]a =\dfrac { (22 \rm \ m/s)^2}{(50\rm \ m)}\\\\a = 9.68\rm \ m/s^2[/tex]
So, the centripetal force is
[tex]F = ma[/tex]
Where, m is the mass = 1200 kg
So,
[tex]F= 1200\rm \ kg\times 9.68\rm \ m/s^2 \\\\F = 11,616\rm \ N[/tex]
Therefore, the truck needs 11,616 N of centripetal force to bend around a radius 50 m.
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What can you infer from the fact that metals are good conductors of electricity?
Answer:
Knowing that these metals are infact good conductors of electricity we can infer that metals are able to hold and conduct certain temperatures. Another thing we can infer is that these good conductors can be used in connection to transferring energy or electricity.
WHAT DOES DENSITY HAVE TO DO WITH PLATE TECTONICS?
Explain
Answer: The reason for the differences in density is the composition of rock in the plates. When two plates come in contact with each other through plate tectonics, scientists can use the density of the plates to predict what will happen. Whichever plate is more dense will sink, and the less dense plate will float over it.
Explanation:
Hope this helps ( not copied and pasted, this answer was done by me so I don't know if it's good or not)
Question 2 of 15
The molar mass of a gas is
OA. a constant for all gases
D B. dependent on the type of gas
C. the mass of a mole of the gas
DD. dependent on the temperature
Answer:
I think it's C
Explanation:
Molar mass (M) is equal to the mass of one mole of a particular element or compound; as such, molar masses are expressed in units of grams per mole (g mol–1) and are often referred to as molecular weights. The molar mass of a particular gas is therefore equal to the mass of a single particle of that gas multiplied by Avogadro’s number (6.02 x 1023 ). To find the molar mass of a mixture of gases, you need to take into account the molar mass of each gas in the mixture, as well as their relative proportion.
to determine the height of a steep cliff an experimenter stations a sensor on the top of the cliff then fires a pellet vertically upward with an initial velocity of 80 m/s . the sensor reports that the pellet reached a maximum height 3 meters above the edge of the cliff. how high is the cliff?
a. 77 m
b. 237 m
c. 317 m
d. 637 m
e. 797 m
Answer:
c. 317 m
Explanation:
Vertical Launch Upwards
It occurs when an object is launched vertically up without taking into consideration any kind of friction with the air.
If vo is the initial speed and g is the acceleration of gravity, the maximum height reached by the object is given by:
[tex]\displaystyle h_m=\frac{v_o^2}{2g}[/tex]
We'll assume the acceleration of gravity as [tex]g=10\ m/s^2[/tex].The pellet is vertically upward launched with vo=80 m/s. The maximum height is:
[tex]\displaystyle h_m=\frac{80^2}{2*10}=320[/tex]
[tex]h_m = 320\ m[/tex]
That height is 3 meters above the edge of the cliff, thus the cliff is 320-3=317 m hight
c. 317 m
g You heard the sound of a distant explosion (3.50 A/10) seconds after you saw it happen. If the temperature of the air is (15.0 B) oC, how far were you from the site of the explosion
Answer:
The answer is "1557 meters".
Explanation:
speed of sound in ([tex]\frac{m}{s}[/tex]) [tex]= 331.5 + 0.60 \ T^{\circ}\ C\\\\[/tex]
[tex]\to V = 331.5 + 0.6 \times 24 = 346 \frac{m}{s}\\\\\to t = 4.5 \ seconds \\\\\to S = vt = 346 \times 4.5 = 1557 \ meters[/tex]
Two satellites orbit the same planet. if a satellite A has an orbit radius r and satellite B has an orbit radius 2r, find the ratio of the period of satellite B to the period of satellite A.
Given :
Two satellites orbit the same planet. if a satellite A has an orbit radius r and satellite B has an orbit radius 2r.
To Find :
The ratio of the period of satellite B to the period of satellite A.
Solution :
We know, square of time period (T) is directly proportional to cube root of radius (r) .
So,
[tex]\dfrac{T_B^2}{T_A^2}=\dfrac{(2r)^3}{r^3}\\\\\dfrac{T_B}{T_A}=2\sqrt{2}[/tex]
Therefore, the ratio of the period of satellite B to the period of satellite A is 2√2 .
The speed of revolution of particle going around a circlr is doubled and its angular speed is havled. What happen to the centripetal acceleration?
a) unchanged
b) doubles
c) halves
d) becomes four times
Answer: The correct answer is C
Explanation:
A truck pushes a pile of dirt horizontally on a frictionless road with a net force of
20
N
20N20, start text, N, end text for
15.0
m
15.0m15, point, 0, start text, m, end text.
How much kinetic energy does the dirt gain?
Answer:
300 JoulesExplanation:
This is a common question on Khan Academy's "Calculating change in kinetic energy from a force" practice exercises. (AP Physics 1)
The simplest method to use is the following: [tex]W = F * d * cos(theta)[/tex], where W represents work (joules), F represents force (newtons), d represents distance (meters), and theta represents the angle of the force that's being applied.In this scenario, the force being applied is horizontal, so we can remove the [tex]cos(theta)[/tex] from our equation.So, our equation is now: [tex]W = F * d[/tex]. This would mean that [tex]W = 20 * 15[/tex], which is equal to [tex]300[/tex]. Our answer is 300 joules. (this value is positive and not negative because kinetic energy is being GAINED, not LOST)Here's the real question without all the formatting:
A truck pushes a pile of dirt horizontally on a frictionless road with a net force of 20 N for 15.0 m. How much kinetic energy does the dirt gain?A truck pushes a pile of dirt in the horizontal direction with a force of 20 N to a distance of 15 m then the kinetic energy of the dirt is 300 J.
What is work?In physics, the term "work" refers to the measurement of energy transfer that takes place when an item is moved over a distance by an externally applied, at least a portion of which is applied inside the direction of the displacement.
The duration of the path is multiplied by the component of a force acting along the path to calculate work if the forces are constant. The work W is theoretically equivalent to the pressure f times the range d, or W = fd, to represent this idea. Work is done when a force is applied at an angle of to a displacement, or W = fd cos.
The work done, [tex]W = Force * Displacement[/tex]
W = 15× 20
W = 300 J
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A 5 kg block rests on an inclined plane with a coefficient of static friction equal to 0.30. What is the minimum angle at which the block will begin to slide
Answer:
[tex]\theta = 16.70 ^{\circ}[/tex]
Explanation:
The coefficient of static friction is equal to the tangent of the minimum angle at which an object will begin to start sliding down a ramp.
[tex]\displaystyle u_s=\frac{F_f}{F_N} = \frac{F_g\ \text{sin}\theta}{F_g\ \text{cos} \theta} = \text{tan} \theta[/tex]Since we are given the coefficient of static friction we can solve for the minimum angle that the block will begin to slide.
Let's solve for the force of gravity that is acting on the block. The force of gravity is also known as the weight force, which can be calculated by using w = mg.
[tex]w=mg[/tex]We are given the mass of the block (kg) and we know that g = 9.8 m/s².
[tex]w=(5)(9.8) = 49 \ \text{N}[/tex]Now we can use this force in the equation:
[tex]\displaystyle u_s = \frac{F_g \ \text{sin} \theta }{F_g \ \text{cos} \theta}[/tex]Plug [tex]\displaystyle u_s = 0.30[/tex] and 49 N into the equation.
[tex]\displaystyle 0.30 = \frac{(49) \ \text{sin} \theta }{(49) \ \text{cos} \theta}[/tex] [tex]0.30=\text{tan} \theta[/tex]Notice that the gravitational force cancels out in the end, so we can actually start with [tex]0.30=\text{tan} \theta[/tex].
Evaluate this equation by taking the inverse tangent of both sides of the equation.
[tex]\text{tan}^-^1 (0.30) = \text{tan}^-^1 (\text{tan}\theta)[/tex] [tex]\text{tan}^-^1 (0.30) =\theta[/tex] [tex]\theta = 16.69924423[/tex]The minimum angle at which the block will begin to slide is about 16.70 degrees.
A ball is throw at an angle of 30 degrees off the horizontal, with an initial velocity of 28 m/s. what is the maximum height the ball will reach?
[tex]{\mathfrak{\underline{\purple{\:\:\: Given:-\:\:\:}}}} \\ \\[/tex]
[tex]\:\:\:\:\bullet\:\:\:\sf{Angle \ of \ projection = 30^{\circ} }[/tex]
[tex]\:\:\:\:\bullet\:\:\:\sf{Initial \ velocity \ of \ projectile = 28 \: m/s^{-1} }[/tex]
[tex]\\[/tex]
[tex]{\mathfrak{\underline{\purple{\:\:\:To \:Find:-\:\:\:}}}} \\ \\[/tex]
[tex]\:\:\:\:\bullet\:\:\:\sf{Height_{\:(max)}\: reached\: by \:the \:projectile }[/tex]
[tex]\\[/tex]
[tex]{\mathfrak{\underline{\purple{\:\:\: Calculation:-\:\:\:}}}} \\ \\[/tex]
☯ As we know that,
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{ H = \dfrac{u^2\;sin^2\theta}{2\;g} }[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{H = \dfrac{(28)^2\;sin^2 30^{\circ}}{2\;(9.8)} }[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{H = \dfrac{784 \times \;sin^230^{\circ}}{19.6} }[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times sin^2 30^{\circ}}[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times \bigg(\dfrac{1}{2}\bigg)^2 }[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times \dfrac{1}{4} }[/tex]
[tex]\\[/tex]
[tex]\dashrightarrow\:\: {\boxed{\sf{H=10\:m }}}[/tex]
N
Using the graph below, how many adults do NOT carpool to work?
Transportation to Work
Account
80
ashboard
70
60
50
Dunes
Number of Adults
40
30
Hondar
20
10
DOK
0
Bus
Walk
Car
Carpool
Method of Transportation
cory
2
160
O 15
50
130
Answer:130
Explanation:just answered it
A 1 200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 8.0 m/s2. How far does the car travel before it stops?
Answer:
Δx = 39.1 m
Explanation:
Assuming that deceleration keeps constant during the braking process, we can use one of the kinematics equations, as follows:[tex]v_{f} ^{2} - v_{o} ^{2} = 2* a * \Delta x (1)[/tex]
where vf is the final velocity (0 in our case), v₀ is the initial velocity
(25 m/s), a is the acceleration (-8.0 m/s²), and Δx is the distance
traveled since the brakes are applied.
Solving (1) for Δx, we have:[tex]\Delta x = \frac{-v_{o} ^{2} }{2*a} = \frac{-(25m/s)^{2}}{2*(-8.0m/s2} = 39.1 m (2)[/tex]
The car will travel a distance of 39.1 m before its stops.
To solve the problem above, use the equations of motion below.
Equation:
v² = u²+2as................... Equation 1Where:
v = final velocity of the automobileu = initial velocity of the automobilea = accelerations = distance coveredFrom the question,
Given:
v = 0 m/s (before its stops)u = 25 m/sa = -8 m/s² (decelerating)Substitute these values into equation 1
⇒ 0² = 25²+2(-8)(s)Solve for s
⇒ 0²-25² = -16s⇒ -16s = -625⇒ s = -625/16⇒ s = 39.1 mHence, The car will travel a distance of 39.1 m before its stops.
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20 pts
Which of the following statements is true?
1..LIghtning is a form of statlc energy.
2..Water Is a conductor of electricIty.
3Electricity must flow in a complete circuit.
4 all of the above
Answer: 2
Explanation:
:}
On Venus, the atmospheric temperature is a hot 720 K due to the greenhouse effect. It consists mostly of carbon dioxide (molar mass 44 g/mol) and the pressure is 92 atm. What is the total translational kinetic energy of 3 moles of carbon dioxide molecules?
Answer:
The value is [tex]E_t = 17958.2 \ J[/tex]
Explanation:
From the question we are told that
The atmospheric temperature is [tex]T_a = 720 \ K[/tex]
The molar mass of carbon dioxide is [tex]Z = 44 \ g/mol[/tex]
The pressure is [tex]P = 92 \ atm =[/tex]
The number of moles is [tex]n = 3 \ moles[/tex]
Generally the translational kinetic energy is mathematically represented as
[tex]E_t = \frac{f}{2} * n * R T[/tex]
Here R is the gas constant with value [tex]R = 8.314 J\cdot K^{-1}\cdot mol^{-1}[/tex]
Generally the degree of freedom of carbon dioxide in terms of translational motion is f = 3
So
[tex]E_t = \frac{ 3}{2} * 2 * 8.314 * 720[/tex]
=> [tex]E_t = 17958.2 \ J[/tex]
which of the following is true? for this graph.
a. the object increase its velocity.
b. the object decrease its velocity.
c. the objects velocity stays unchanged.
d. the object stays at rest.
e. more information is required.
Answer:
b. The objects velocity is decreasing.
Explanation:
I know this because if you read a graph left to right it will tell u whether it is increasing or decreasing.
A 950 kg car rounds an unbanked curve at a speed of 25 m/s. If the radius of the curve is 72 m, what is the minimum coefficient of friction between the car and the road required so that the car does not skid?
Compute the car's weight:
W = m g = (950 kg) (9.8 m/s²) = 9310 N
The net vertical force on the car is
∑ F = N - W = 0
so the normal force has magnitude
N = W = 9310 N
Then the friction force that keeps the car from skidding has magnitude F = µ N, where µ is the coefficient of friction, and it's friction that makes up the net horizontal force on the car. By Newton's second law, we have
F = m a
µ N = m v ² / R
µ (9310 N) = (950 kg) (25 m/s)² / (72 m)
µ ≈ 0.89