Answer:
power per square meter = 4.593 × 10^(6) W/m²
Wavelength of peak intensity = 9.67 × 10^(-7) m
Explanation:
From Stefan-Boltzmann law, total emitted power per square meter is given as;
P/A = eσT⁴
where;
P is power
A is surface area
σ = Stefan-Boltzmann constant = 5.67 × 10^(-8) W/m².k⁴
T = temperature of the body = 3000 K
e = emissivity of the substance (for ideal radiation, it has a value = 1)
Thus, Plugging in the relevant values we have;
P/A = 1 × 5.67 × 10^(-8) × (3000)^(4)
P/A = 4.593 × 10^(6) W/m²
Let's find the wavelength of peak intensity.
From wiens displacement law, we know that;
λ_m × T = b
where;
λ_m = maximum wavelength
T = Temperature
b is Wien's displacement constant = 2.9 × 10^(−3) m/K
thus;
λ_m = b/T = (2.9 × 10^(−3))/3000 = 9.67 × 10^(-7) m
What are the poles of a bar magnet.is it North West South or east.
Answer:
One end of any bar magnet will always want to point north if it is freely suspended. This is called the north-seeking pole of the magnet, or simply the north pole. The opposite end is called the south pole.
Explanation:
Answer:
North Pole and South Poles
Explanation:
There is no east or west in a magnetic field of a magnet. The magnetic field lines comes from North pole to south pole.
Which best compares radiation and conduction?
C Both transfer thermal energy from warm objects to cooler objects.
O Both can transfer energy through empty space.
O Both transfer thermal energy by electromagnetic waves.
O Both involve the transfer of energy through direct contact.
Answer:
The statements that best compares radiation and conduction are the following: both transfer thermal energy from warm objects to cooler objects and both can transfer energy through matter. The difference is that conduction is through direct heat transfer; whereas, radiation transfers heat through waves.
WILL MARK BRAINLIEST
Answer:
152,155 J
Explanation:
115,333 + 36,822 = 152,155J
If a driver makes contact with a steering wheel during a 35 mph crash, she comes to rest in about Δ=15 ms. If, during an identical crash, the driver makes contact with an air bag, she comes to rest in about Δ=110 ms. What is the ratio of the force exerted by the steering wheel to the force exerted by the air bag on the driver?
Answer:
The ratio of forces is 22 : 3.
Explanation:
Case I:
initial velocity, u = 35 mph
final velocity, v = 0
time, t = 15 ms
Case II:
initial velocity, u = 35 mph
final velocity, v = 0
time, t' = 110 ms
let the mass is m.
According to the Newton's second law, the force is given by the rate of change of momentum.
So
[tex]F =\frac{m(v-u)}{t}\\\\F'= \frac{m(v-u)}{t'}\\\\So, \frac{F}{F'} =\frac{t'}{t}\\\\\frac{F}{F'}=\frac{110}{15}=22:3[/tex]
1o4 Fahrenheit is equal to
Answer:
40 degrees Celsius
Explanation:
Have a great summer :)
10.
You are standing on a sheet of ice that covers the football stadium parking lot in Buffalo; there is
negligible friction between your feet and the ice. A friend throws you a 0.4 kg ball that is traveling
horizontally at 10 m/s. Your mass is 70 kg. If you catch the ball, with what speed do you and the ball
move afterwards?
1.02 m/s
0.06 m/s
0.02 m/s
0.12 m/s
Answer:
Explanation:
This is a classic Law of Momentum Conservation problem. For us the equation will look like this:
[tex][(m_yv_y+m_bv_b)]_b=[(m_y+m_b)v_{both}]_a[/tex] Filling in with our given info:
[tex][(70.0)(0)+(.40)(10.0)]_b=[(70.0+.40)v_{both}]_a[/tex] and
4.0 = 70.4v and
v = .06 m/s
The switch is released and the door locks. Explain in detail how this happens.
Answer:
The iron bolt is attracted to the electromagnet. The force of attraction between the electromagnet's core and the iron bolt is greater than the force of the spring, so the iron bolt is pulled out of its housing in the door
Explanation:
A woman pushes a car with a force of 400 N for a distance of 15m. How much work has she done?
Answer:
the work done by the woman is 6,000 J
Explanation:
Given;
force applied by the woman, F = 400 N
distance moved by the woman, d = 15 m
The work done by the woman is calculated as follows;
W = F x d
W = 400 N x 15 m
W = 6000 Nm = 6,000 J
Therefore, the work done by the woman is 6,000 J
when a metal ball is heated through 30°c,it volume becomes 1.0018cm^3 if the linear expansivity of the material of the ball is 2.0×10^-5k^-1, calculate its original volume
A exerted by an object on another is a force
hope this helps
Answer:
If a person is pushing a desk across the room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person.
The initial momentum of a system is measured at 300 kg•m/s. Afterwards, the
momentum is measured to be 280 kg•m/s. What is the impulse of the system?
Two friends are working out together using weights:
-James lifts 20kg weights up at a velocity of 1.9m/s
-Kayla lifts 15kg weights up at a velocity of 2.6m/s
0
Which friend is creating more momentum?
Answer:
Kayla. You can calculate it using the formula for momentum: momentum=mass×velocity and find the bigger number between the two momentums
What is the gravitational force between two objects?
Answer:
Gravitational force -an attractive force that exists between all objects with mass; an object with mass attracts another object with mass; the magnitude of the force is directly proportional to the masses of the two objects and inversely proportional to the square of the distance between the two objects.
Explanation:
hope it helped
In which of these media will mechanical waves travel the slowest in?
a Plastic
b Butter
C Ice
d Air
e Steel
Answer:
E
Explanation:
it has more mass
The medium in which mechanical waves will travel the slowest in is air which is gaseous medium.
What is mechanical wave?A mechanical wave is a type of wave that requires material medium for its propagation.
An example of mechanical wave is sound wave because sound wave requires material medium for its propagation.
Sound waves travel fastest in solid, followed by liquid, then least in gasous medium.
Thus, the medium in which mechanical waves will travel the slowest in is air which is gaseous medium.
Learn more about mechanical waves here: https://brainly.com/question/9242091
A 500-kg crate sits on a 10-degree ramp. If friction between the ramp and the crate is 800 N, what is the acceleration of the crate?
By Newton's second law, the net force acting on the crate parallel to the surface is
∑ F = mg sin(10°) - 800 N = ma
where m = 500 kg is the mass of the crate and a is the acceleration.
Solve for a :
a = ((500 kg) (9.80 m/s^2) sin(10°) - 800 N) / (500 kg)
a ≈ 0.102 m/s^2
describe 2 ways you could increase the efficiency of a household central heating system
Answer:
Arrange an annual service. Treat your boiler like your car. ...
Keep your boiler clean. ...
Bleed your radiators. ...
Top up the pressure. ...
Use a Powerflush. ...
Insulate your pipes. ...
Turn the heating on. ...
If all else fails…
Explanation:
When you flip a penny (2.35 g), it leaves your hand and moves upward at 2.85 m/s. Use energy to find how high the penny goes above your hand before stopping. A (b) The penny then falls to the floor, 1.26 m below your hand. Use energy to find its speed just before it hits the floor. A (c) Explain your choice of reference level for parts (a) and (b). C (d) Choose a different reference level and repeat part (b)
Answer:
a. 0.41 m
b. 5.72 m/s
c. i. For part (a), I chose the hand as the reference level since the penny was thrown from the hand and the height of the penny at the hand is zero and also, it is easier to calculate from a zero reference level.
ii. For part (b), I chose the ground as the reference level since the height of the penny above the ground is positive and the height of the penny when the penny hits the ground is zero and also, it is easier to calculate from a zero reference level.
d. 5.72 m/s
Explanation:
a. Use energy to find how high the penny goes above your hand before stopping.
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy at the hand, E equals the total mechanical energy when the penny stops in the air, E'.
E = E'
U + K = U' + K' where U = initial potential energy at hand level = mgh where h = height at hand level = 0, K = initial kinetic energy at hand level = 1/2mv² where v = speed at hand level = 2.85 m/s, U' = final potential energy at stopping level = mgh' where h' = height at stopping level, K = final kinetic energy at stopping level = 1/2mv'² where v = speed at stopping level = 0 m/s (since the penny momentarily stops)
So, U + K = U' + K'
mgh + 1/2mv² = mgh' + 1/2mv'²
substituting the values of the variables into the equation, we have
mg(0) + 1/2m(2.85 m/s)² = mgh' + 1/2m(0 m/s)²
0 + 1/2m(8.1225 m²/s²) = mgh' + 0
m(4.06125 m²/s²) = mgh'
h' = 4.06125 m²/s² ÷ g
h' = 4.06125 m²/s² ÷ 9.8 m/s²
h' = 0.41 m
(b) The penny then falls to the floor, 1.26 m below your hand. Use energy to find its speed just before it hits the floor.
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy when the penny stops in the air, E' equals the total mechanical energy on the ground, E"
E' = E"
U' + K' = U" + K" where U' = initial potential energy at stopping level = mgh" where h' = height at stopping level = height of penny above hand, h' + height of hand above ground = 0.41 m + 1.26 m = 1.67 m, K = initial kinetic energy at stopping level = 1/2mv'² where v = speed at stopping level = 0 m/s (since the penny momentarily stops), U = final potential energy at ground level = mgh₁ where h₁ = height at ground level = 0, K = final kinetic energy at ground level = 1/2mv"² where v" = speed at ground level,
So, U' + K' = U' + K'
mgh" + 1/2mv'² = mgh₁ + 1/2mv"²
substituting the values of the variables into the equation, we have
mg(1.67 m) + 1/2m(0 m/s)² = mg(0) + 1/2mv"²
1.67mg + 0 = 0 + 1/2mv"²
1.67mg = 1/2mv"²
1.67g = 1/2v"²
v"² = 2(1.67g)
v" = √[2(1.67g)]
v" = √[2(1.67 m × 9.8 m/s²)]
v" = √[2(16.366 m²/s²)]
v" = √[32.732 m²/s²)]
v" = 5.72 m/s
(c) Explain your choice of reference level for parts (a) and (b).
i. For part (a), I chose the hand as the reference level since the penny was thrown from the hand and the height of the penny at the hand is zero and also, it is easier to calculate from a zero reference level.
ii. For part (b), I chose the ground as the reference level since the height of the penny above the ground is positive and the height of the penny when the penny hits the ground is zero and also, it is easier to calculate from a zero reference level.
(d) Choose a different reference level and repeat part (b)
Taking the hand as the ground level, and from the law of conservation of energy, the total mechanical energy when the penny stops in the air, E' equals the total mechanical energy on the ground, E"
E' = E"
U' + K' = U" + K" where U' = initial potential energy at stopping level = mgh' where h' = height at stopping level = 0.41 m, K = initial kinetic energy at stopping level = 1/2mv'² where v' = speed at stopping level = 0 m/s (since the penny momentarily stops), U = final potential energy at ground level = mgh₁ where h₂ = height of hand above the ground level = height of ground below hand = -1.26 m(it is negative since the ground is below the hand), K = final kinetic energy at ground level = 1/2mv"² where v = speed at ground level,
So, U' + K' = U' + K'
mgh' + 1/2mv'² = mgh₂ + 1/2mv"²
substituting the values of the variables into the equation, we have
mg(0.41 m) + 1/2m(0 m/s)² = mg(-1.26 m) + 1/2mv"²
0.41mg + 0 = -1.26 mg + 1/2mv"²
0.41mg + 1.26mg = 1/2mv"²
1.67mg = 1/2mv"²
1.67g = 1/2v"²
v"² = 2(1.67g)
v" = √[2(1.67g)]
v" = √[2(1.67 m × 9.8 m/s²)]
v" = √[2(16.366 m²/s²)]
v" = √[32.732 m²/s²)]
v" = 5.72 m/s
a car travelled at 50km/hr for 3 hours, how far did the car travel
Answer:
The answer answer is 150 km
Answer:
Explanation:
Distance =Speed×time
Speed=50km/hr
Time=3hours
Hence the Distance will be(50km/hr×3hours)
The answer is 150km
A 1500 kg truck travelling north at 60 km/hr collides with a 1200 kg car moving east at 15km/hr. If the two cars remain locked together after impact, with what velocity do they move immediately after the collision.
Answer:
33.33j+6.67i km/hr
Explanation:
From the law of conservation of momentum,
Applying,
mu+m'u' = V(m+m')............... Equation 1
Where m = mass of the truck, m' = mass of the car, u = initial velocity of the truck, u' = initial velocity of the car, V = Final velocity.
Note: let j represent the north, and i represent the east
From the question,
Given: m = 1500 kg, u = 60j, m' = 1200 kg, u' = 15i
Substitute these values into equation 1
1500*60j+1200*15i = V(1500+1200)
90000j+18000i = 2700V
V = (90000j+18000i)/2700
V = 33.33j+6.67i km/hr
A 52 kg child on a swing is travelling at 6 m/s . What is his gravitational potential energy if he has 1000 J of the mechanical energy?
Answer:
The correct answer is "64 J".
Explanation:
The given values are:
Mass,
m = 52 kg
Velocity,
v = 6 m/s
Mechanical energy,
= 1000 J
Now,
The gravitational potential energy will be:
⇒ [tex]P.E=1000-\frac{1}{2}mv^2[/tex]
[tex]=1000-\frac{1}{2}\times 52\times (6)^2[/tex]
[tex]=1000-26\times 36[/tex]
[tex]=1000-936[/tex]
[tex]=64 \ J[/tex]
which type of material is the best sound absorber?
a. glass
b. wood
c. concrete
d. carpet
Explanation:
Glass is the best sound absorber material.
True or false please help I’ll give brainliest
Answer:
1 is false 2 is true 3 is false
The Statue of Liberty is made of Copper that has turned on Says has WAGNE Bongo Wantse
said about this change?
The change is a physical change because the owner in the same is still there,
The change is a physical change beave a new chemical is was on the outside of the sale,
The change is not a physical change beans the plos at the stanje na dana),
The change is nga physical change because a new chemical istmes on the outside of the stalye
Complete Question:
The Statue of Liberty is made of copper that has turned green because it has undergone a change. What can be said about this change?
Group of answer choices.
A. The change is a physical change because the copper in the statue is still there.
B. The change is a physical change because a new chemical is formed on the outside of the statue.
C. The change is not a physical change because the color of the statue has changed.
D. The change is not a physical change because a new chemical is formed on the outside of the statue.
Answer:
D. The change is not a physical change because a new chemical is formed on the outside of the statue.
Explanation:
A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.
This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.
Additionally, a physical change is a type of change that involves an increase or decrease in the volume of a physical object (object). Also, this change can be reversed to the original state under certain conditions.
Since the Statue of Liberty which is made of copper turned green, the change is not a physical change because a new chemical is formed on the outside of the statue.
Mr. Tolman believes that our universe is expanding, but with all of the gravitational force from the celestial bodies of space, the universe will begin to contract. He believes in the _____.
A) oscillating universe theory
B) inflation theory
C) steady state theory
D) big bang theory
a) How much electrical energy, in joules, does a 1000W space heater consume when it runs for 8h? (b) How much energy is that in kilowatt hours? (c) Calculate the cost of using this heater if 1kWh costs 0.5 dollars.
Answer:
a. Energy = 28800000 Joules
b. Energy = 8 Kwh
c. Cost = $4
Explanation:
Given the following data;
Power = 1000 Watts
Time = 8 hours
Cost = $0.5 per KWh
Conversion:
1 hour = 60 * 60 = 3600 seconds
8 hour = 8 * 3600 = 28800 seconds
a. To find much electrical energy, in joules;
Energy = power * time
Energy = 1000 * 28800
Energy = 28800000 Joules
b. To find how much energy is that in kilowatt hours;
Energy = power * time
Energy = 1000 * 8
Energy = 8000 Watt-hour = 8000/1000 = 8 Kwh (1 Kilowatts is equal to 1000 watts).
c. To calculate the cost of using this heater;
Cost = 8 * 0.5
Cost = $4
calculate:An elcetric lamp is rated 240V and 40W. What is the cost of running the lamp for 62 hours if the elctricity authorities charges #2.50k per KWH
Explanation:
The voltage of the lamp, V = 240 V
Power of the lamp, P = 40 W
It is running for 62 hours.
The cost of running is $2.50k per KWH
Electric power is,
P = 40×62 Wh
= 2480 Wh
P = 2.48 kWh
At the rate of $2.5 per kWh
P = $6.2
So, the cost of running is $6.2 per kWh.
B
oc
OD
A metal has a specific heat capacity of 360J/(kg°C).
An object made of this metal has a mass of 2.0kg.
What is the thermal capacity (heat capacity) of the object?
Answer:
Thermal capacity of the object = 720 j/°C
Explanation:
Given:
Specific heat capacity of metal = 360J/(kg°C)
Mass of given object = 2 kg
Find:
Thermal capacity of the object
Computation:
Thermal capacity = Specific heat x Mass
Thermal capacity of the object = Specific heat capacity of metal x Mass of given object
Thermal capacity of the object = 360 x 2
Thermal capacity of the object = 720 j/°C
The isotope used to remove cancer malignancy cell the given options are a. Strontium 89 b. Uranium 238 c. Carbon 14 d. Chlorine 37.......... can anyone tell me the ans plzz
Answer:
B. Uranium 238.
Explanation:
It is radioactive and can be used to treat cancer in the form of radiotherapy
VI. A student attaches four drawing pins to a copper rod using candle wax as shown in the diagram
The rod is then heated continuously at one end and the pins fall off in the order 4, 3, 2, 1
Explanation:
[tex]C.) \: Conduction \: \\ \\ = > it \: is \: a \: process \: of \: transferring \: \\ \\ of \: heat \: from \: one \: object \: to \: another \\ \\ when \: they \: are \: in \: contact \: [/tex]
By the conduction process the heat reaches the pin.Option C is correct.
What is heat transfer?The term "heat transfer" refers to the movement of heat. The flow of heat across a system's boundary is due to a temperature differential between the system and its surroundings.
Conduction is the type of heat transfer occurs mainly in solid or by contact.In the given condition the rod is then heated continuously at one end and the pins fall off in the order 4, 3, 2, 1.
By the conduction process the heat reaches the pin.
Hence option C is correct.
To learn more about the heat transfer refer to the link;
https://brainly.com/question/13433948
#SPJ2
You throw a water balloon straight up with a velocity of 13 m/s. What is its
maximum height?
O A. 4.4 m
B. 6.3 m
C. 10.7 m
D. 8.6 m
Answer:
Explanation:
[tex]h=-v^2 /2g[/tex]
[tex]with\\g = 9,8 m/s^2 or 10 m/s^2[/tex]
[tex]h= (-13)^2 / 2 * 9,8 = 8,6[/tex]
