Answer:
The rate of heat transfer of the second object is greater than the first object.
Explanation:
[tex]\varepsilon[/tex] = Emissivity of the object
[tex]\sigma[/tex] = Stefan-Boltzmann constant = [tex]5.67\times 10^{-8}\ \text{W/m}^2/\text{K}^4[/tex]
[tex]T_1[/tex] = Temperature of surface 1 = [tex]25^{\circ}\text{C}+273.15=298.15\ \text{K}[/tex]
[tex]T_2[/tex] = Temperature of surface 2 = [tex]40^{\circ}\text{C}+273.15=313.15\ \text{K}[/tex]
[tex]T_0[/tex] = Surrounding temperature = [tex]25^{\circ}\text{C}+273.15=298.15\ \text{K}[/tex]
Rate of heat transfer is given by
[tex]P_1=\varepsilon \sigma (T_1^4-T_0^4)\\\Rightarrow P_1=\varepsilon \sigma A_1(298.15^4-298.15^4)\\\Rightarrow P_1=0\ \text{W}[/tex]
[tex]P_2=\varepsilon \sigma (T_2^4-T_0^4)\\\Rightarrow P_2=\varepsilon 5.67\times10^{-8} A_2(313.15^4-298.15^4)\\\Rightarrow P_2=\varepsilon A_297.2[/tex]
[tex]\varepsilon A_297.2>0[/tex]
So, [tex]P_2>P_1[/tex]
Hence, the rate of heat transfer of the second object is greater than the first object.
A woman has a mass of 55 kg on earth. what would be the women's weight on the moon? (The moon’s gravity is 1.6 N).
Answer:
i dont know the answer sorry have a good day
Explanation:
hsjsjdkdkdkdkdkdk
A3.0 105 kg freight car moving at 2.5 m/s east, strikes a
stationary 1.5 x 105 kg car. If the two cars end up connected
to each other, what is their resulting velocity?
Answer:3.4 miles west
Explanation:
The (nonconservative) force propelling a 1.50 103-kg car up a mountain road does 5.10 106 J of work on the car. The car starts from rest at sea level and has a speed of 24.0 m/s at an altitude of 2.20 102 m above sea level. Obtain the work done on the car by the combined forces of friction and air resistance, both of which are nonconservative forces.
We know, Work done by all the forces is equal to change in potential energy :
[tex]W_{friction} + W_{air} + W_{engine} = \dfrac{(mv_f^2 + mgh_f)}{2}-\dfrac{(mv_i^2+mgh_i)}{2}[/tex]
Here,
[tex]h_i=0\ m\\\\v_i = 0\ m/s[/tex]
Putting all given values, we get :
[tex]W_{friction} + W_{air} + 5.10\times 10^6 = m\dfrac{(v_f^2 + gh_f)}{2}-0\\\\W_{friction} + W_{air} =1.5\times 10^3 \times \dfrac{(24^2 + (9.8\times 2.2\times 10^2))}{2}-5.10\times 10^6\\\\W_{friction} + W_{air} = -3.051\times 10^6\ J[/tex]
Hence, this is the required solution.
Why would the solstice be important to
an ecosystem?
Answer:
marks an important milestone. It's the shortest day of the year and the longest night of the year, and signals a powerful transition point between seasons that is impossible to ignore. ... In Pagan times the winter solstice was referred to as Yule and was a celebration of the Goddess (Moon) energy
Explanation:
Why does the Sun appear white at noon?
What is the mathematical relationship between wavelength and velocity? PLZ HELP MEEE
Answer: wavelength is the length of the wave, example the length of a sound wave.
Velocity is also known as speed.
Explanation:
You walk exactly 250 steps North, turn around, and then walk exactly 400 steps South. How far are you from your starting
point?
steps to the
North, South, East or West)
Answer:
150 steps south
Explanation:
250 north 250 back to start then continue south for remainder of 400 steps. 150 south
I am traveling at 100 m/s, I hit the brakes and my speed goes down to 50 m/s. It took 30 seconds to slow down. What was my acceleration?
A.5 m/s2
B.-5 m/s2
C.1.7 m/s2
D.-1.7 m/s2
Answer:
D. -1.7m/s2
Explanation:
the car starts at 100m/s so this is the initial velocity. It ends at 50m/s so this is the final velocity. it took 30 seconds so the time is 30.
[tex]v_{f}=v_{i}+at[/tex]
[tex]a=\frac{\left(v_{f}-v_{i}\right)}{t}[/tex]
[tex]a=\ \frac{\left(50-100\right)}{30}[/tex]
[tex]a=-1.66666666667[/tex][tex]m/s^{2}[/tex]
Therefore, the answer is D
Two forces act in opposite directions on a wood block. What will happen if the forces are unbalanced?
A. The block will balance the forces.
B. The forces will reverse direction.
C. The mass of the block will change.
D. The position of the block will change.
Answer:
D
Explanation:
If two unequal forces act in opposite directions, one larger force must cancel out the smaller force,
leaving the net force to be some number in one direction.
Take for example a game of tug-of-war; there are two OPPOSITE forces (groups of people) acting on the rope, one force is pulling with a force in the negative direction while the other force is pulling in the positive direction.
If the forces on the rope were unequal, then the stronger force (group) will pull everything in their direction.
The same will happen on two unequal forces of opposite directions acting on a wooden block. Therefore, since the resultant force will have a non-zero magnitude and direction, there will be a change in the block's motion and position.
The negatively charged particle in an atom is a(n):
Answer: Electron
Explanation:A negatively charged particle found circling or orbiting an atomic nucleus. An electron, like a proton is a charged particle, although opposite in sign, but unlike a proton, an electron has negligible atomic mass. Electrons contribute no atomic mass units to the total atomic weight of an atom.
Hope this helps!!Brainlist?
What is string theory? Need answer in own word
Answer:
When point particals are replaced by string like particals
Explanation:
The accepted equations for force and elastic potential energy for a spring include a term called the spring constant, k (in N/m). How could you find the spring constant from a force vs displacement graph? Explain.
Explanation:
Accordibg to Hooke's law ,
F=-kx
the minus sign indicates that the force exerted by the spring is opposite to that of extension and the relation between force and extension is a linear one so in the graph it wll pass through the origin and x=0 F=0 and the k (spring constant) will be a constant
A 100 kg skateboarder sits at the top of a 10 m halfpipe, ready to go down the ramp. What will be his velocity when
he is 4 m off of the ground?
Answer:
v = 10.85 m/s
Explanation:
We will apply the law of conservation of energy to the skateboarder. Neglecting the frictional effects, the law of conservation of energy can be written as:
[tex]Loss\ in\ Potential\ Energy\ of\ Skateboarder = Gain\ in\ Kinetic\ Energy\ of\ Skateboarder[/tex][tex]mg\Delta h = \frac{1}{2}mv^2\\\\v^2 = 2g\Delta h\\v = \sqrt{2g\Delta h} \\[/tex]
where,
v = velocity of skateboarder = ?
g = acceleration due to gravity = 9.81 m/s²
Δh = change in height = 10 m - 4 m = 6 m
Therefore,
[tex]v = \sqrt{{(2)(9.81\ m/s^2})({6\ m})}}[/tex]
v = 10.85 m/s
Mr. Davis is riding his bike at a speed of 5 meters per second for 3600 seconds how far did he ride?
Answer:18,000 meters
Explanation:3600x5=18,000.
HELP PLEASE URGENT
If a 0.16 kg 8-ball at rest is hit by the 0.17 kg cue ball that is moving at a speed of 2 m/s, what is the speed of the 8-ball if the cue ball is completely stopped after the collision?
Answer:
The speed of the 8-ball is 2.125 m/s after the collision.
Explanation:
Law Of Conservation Of Linear Momentum
The total momentum of a system of masses is conserved unless an external force is applied. The formula for the momentum of a body with mass m and velocity v is
P=mv
If we have a system of masses, then the total momentum is the sum of them all
[tex]P=m_1v_1+m_2v_2+...+m_nv_n[/tex]
If a collision occurs, the velocities change to v' and the final momentum is:
[tex]P'=m_1v'_1+m_2v'_2+...+m_nv'_n[/tex]
In a system of two masses, the law of conservation of linear momentum takes the form:
[tex]m_1v_1+m_2v_2=m_1v'_1+m_2v'_2[/tex]
The m1=0.16 Kg 8-ball is initially at rest v1=0. It is hit by an m2=0.17 Kg cue ball that was moving at v2=2 m/s.
After the collision, the cue ball remains at rest v2'=0. It's required to find the final speed v1' after the collision.
The last equation is solved for v1':
[tex]\displaystyle v'_1=\frac{m_1v_1+m_2v_2-m_2v'_2}{m_1}[/tex]
[tex]\displaystyle v'_1=\frac{0.16*0+0.17*2-0.17*0}{0.16}[/tex]
[tex]\displaystyle v'_1=\frac{0.34}{0.16}[/tex]
[tex]v'_1=2.125\ m/s[/tex]
The speed of the 8-ball is 2.125 m/s after the collision.
how does a plane mirror work
Answer:
Plane mirrors work because the light rays create a virtual image behind the mirror. Light rays from the object strike the mirror and reflect according to the law of reflection. ... Therefore, our eye and brain track the light rays backward to a position from which they appear to have come.
Bernoulli's principle is responsible for most of the lift produced by an airplane wing.
True
False
Answer:
huiiiiuuu beautiful...
According to newton's second law, if you have an object that is put under acceleration due to a force, how could you reduce the acceleration
Answer:
We could reduce the force or increase the mass of the object.
Explanation:
Using the definition of force, according to Newton's second law, (F = ma) the acceleration is directly proportional to the force and inversely proportional to the mass. Therefore, if we want to reduce the acceleration of an object we have two options:
We could reduce the force We could increase the massIn both cases a will decrease.
I hope it helps you!
The density of a substance is 3.4 g cm-3. Its relative density relative to another substance is 2.0. what is the density of the second substance?
Answer:
1.7 g/cm³
Explanation:
Given that:
Density of substance = 3.4 g/cm³
Relative density to another substance = 2
Density of second substance=?
Let density of second substance = x
Relative density = density of substance / density of second substance
Relative density = density of substance / x
2.0 = 3.4g/cm³ / x
2 * x = 3.4 g /cm³
x = 3.4 g/cm³ ÷ 2
x = 1.7 g/cm³
(b) () State what is meant by specific acoustic impedance.
...........[2]
Answer:
.
Explanation:
.
How much heat is lost by 2.0 grams of water if the temperature drops from 31 °C to 29 °C? The specific heat of water is 4.184 J/(g • °C) *
1 point
a) 4.0 J
b) - 7.5 J
c)- 8.4 J
d) - 16.7 J
Given :
Mass of water, m = 2 grams.
The temperature of water drops from 31 °C to 29 °C .
The specific heat of water is 4.184 J/(g • °C).
To Find :
Amount of heat lost in this process.
Solution :
We know, heat lost is given by :
[tex]Heat\ lost,H = ms( T_f - T_i)\\\\H = 2\times 4.184 \times ( 31 - 29 )\ J\\\\H = 16.736\ J[/tex]
Therefore, amount of heat lost in this process is 16.736 J.
what is the speed of a 330kg beam dropped from 40m
Answer:
28 m/s
Explanation:
We can use this constant acceleration kinematic equation to find the speed of this beam as it is dropped from 40 m.
Since the object is dropped vertically downwards, we know that the object is in free-fall.
The acceleration of this object is -g, which is -9.8 m/s² since we are making the positive direction upwards and the negative direction downwards.
The initial velocity is 0 m/s since the object is dropped and starts from rest.
The final velocity is what we are trying to solve for.
The displacement in the y-direction is 40 m.
Now we can see which equation contains these 4 variables:
v² = v₀² + 2aΔxPlug in the known variables.
v² = (0)² + 2(-9.8)(-40)Simplify this equation.
v² = 784Take the square root of both sides.
v = 28 m/sThe speed of the 330 kg beam dropped from 40 m is 28 m/s.
Answer:
28 m/sExplanation:
Given information :
mass = 330kg
height =40m
v = √2gh
Where ;
g = acceleration due to gravity = 9.8 or 10 m/s
h = height
how much total energy of the beam just as it hits the ground =
mgh
[tex]330\times 10\times 40\\\\\\=132000[/tex]
Speed at which the beam will hit the ground :
[tex]v = \sqrt{2\times 10\times40} \\\\=\sqrt{800}\\\\=20\sqrt{2}\\\\v=28.28427[/tex]
De-Broglie postulated that the relationship, lambda=h/p is valid for relativistic particles. Find out the de-Broglie wavelength for an electron whose kinetic energy is 3MeV.
Given :
An electron with kinetic energy of 3 MeV.
To Find :
The de-Broglie wavelength for that electron.
Solution :
We know, de-Broglie wavelength for an electron with kinetic energy K.E is given by :
[tex]\lambda = \dfrac{h}{\sqrt{2m(K.E)}}[/tex]
Putting all given values in above equation, we get :
[tex]\lambda = \dfrac{6.626\times 10^{-34}}{\sqrt{2\times 9.1\times 10^{-31}\times 3\times 10^6 \times 1.6\times 10^{-19}}}\\\\\\\lambda = 7.089 \times 10^{-13} \ m[/tex]
Hence, this is the required solution.
In Space, an astronaut releases a wrench from his hand. The wrench has a mass of 4 grams and is traveling with a velocity of -15m/s. The Astronaut’s mass is 70kg. What is his Velocity?
Answer:
The velocity of the astronaut is approximately 0.0008571 m/s
Explanation:
The mass of the the wrench, m₁ = 4 grams = 0.004 kg
The velocity of the wrench, v₁ = -15 m/s
The mass of the astronaut, m₂ = 70 kg
The velocity of the astronaut = v₂
Whereby the astronaut and the wrench were initially at rest, we have;
The total initial momentum = 0 kg·m/s
The total final momentum = m₁ × v₁ + m₂ × v₂ = 0.004 kg × (-15 m/s) + 70 kg × v₂
By the conservation of momentum principle, we have;
The total initial momentum = The total final momentum
Therefore, we have;
0 kg·m/s = 0.004 kg × (-15 m/s) + 70 kg × v₂
Which gives;
0.004 kg × (-15 m/s) = 70 kg × v₂
70 kg × -v₂ = 0.004 kg × (-15 m/s)
-v₂ = 0.004 kg × (-15 m/s)/(70 kg) ≈ -0.0008571 m/s
-v₂ ≈ -0.0008571 m/s
v₂ ≈ 0.0008571 m/s
The velocity of the astronaut = v₂ ≈ 0.0008571 m/s
A grinding wheel, initially at rest, is ro-tated with constant angular acceleration of2.52 rad/s2for 7.03 s. The wheel is thenbrought to rest with uniform deceleration in11.9 rev.Find the angular acceleration required tobring the wheel to rest. Note that an in-crease in angular velocity is consistent with apositive angular acceleration.Answer in units of rad/s2.
Starting from rest, the wheel accelerates to an angular velocity of
ω = (2.52 rad/s²) (7.03 s) ≈ 17.7 rad/s
then undergoes a new acceleration α until it comes to a rest. It does so in 11.9 revolutions, or with an angular displacement of (11.9 rev) • (2π rad/rev) = 23.8π rad. So α satisfies
0² - ω² = 2 α (23.8π rad)
α = - ω² / (47.6π rad)
α ≈ -2.10 rad/s²
An icicle falls off of a skyscraper from rest and falls for 34 seconds. How fast will that icicle be moving after that time? Show all work and units. (a = g = 9.81 m/s^2) *
Answer:
The icicle will be moving at 333.54 m/s
Explanation:
Free Fall Motion
A free-falling object falls under the sole influence of gravity. Any object that is being acted upon only by the force of gravity is said to be in a state of free fall. Free-falling objects do not encounter air resistance.
If an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is [tex]g = 9.81 m/s^2[/tex].
The final velocity of a free-falling object after a time t is given by:
vf=g.t
The icicle falls from rest for 34 seconds. We need to find the speed after that time:
vf = 9.81*34
vf = 333.54 m/s
The icicle will be moving at 333.54 m/s
If an object is resting on a surface it "crunches" the atoms underneath it. According to Newton's Third Law the surface pushes back on the object. What is the name given to this force that acts perpendicular to the surface?
Answer:
Normal force
Explanation:
Normal force is the force that surfaces employ so that solid objects are disallowed from passing through each other.
what happens when heat is removed from water? the water particles move farther apart. the water changes from a liquid to a gas. the temperature of the water increases. the kinetic energy of the water particles decreases.
Answer:d
Explanation:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.
Answer:
True
Explanation:
The main differences between a physical property and a chemical property are mentioned below:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points.
While A chemical property describes the ability of a substance to undergo a specific chemical change.
We only see objects because they absorb light.
True or False?
Answer:
true
Explanation:
i think it's true because I took a quiz on this