Given data
Source temperature (T₁) = 177°C = 177+273 = 450 K
Sink temperature (T₂) = 27°C = 27+273 = 300 K
Energy input (Q₁) = 3600 J ,
Work done = ?
We know that, efficiency (η) = Net work done ÷ Heat supplied
η = W ÷ Q₁
W = η × Q₁
First determine the efficiency ( η ) = ?
Also, we know that ( η ) = (T₁ - T₂) ÷ (T₁)
= 33.3% = 0.333
Now, Work done is W = η × Q₁
= 0.33 × 3600
W = 1188 J
Work done by the engine is 1188 J
Which best explains why graphite is a good lubricant? Carbon atoms form strong bonds within each graphite layer but weak bonds between layers. Carbon atoms in graphite form alternating single and double bonds. Each carbon atom in graphite forms weak covalent bonds with three other carbon atoms.
Graphite is great lubricant because each carbon atom forms weak covalent bonds with three other carbon atoms.
Diamond and graphite both are entirely made up of carbon but both the elements are completely different because of the bonding of carbon atoms. In graphite the carbon atoms form weak covalent with the other three carbon atom due to which there is less or no force between the atoms, and makes the graphite very soft and slippery, and graphite act as lubricant.
Answer:
Carbon atoms form strong bonds within each graphite layer but weak bonds between layers.
Explanation:
Graphite is known as solid lubricant which means it is a lubricant which is in the solid state form.
Here we know that lubricant has function to make the relative movement very smooth or easy.
So here in structure of graphite it is formed in such a way that all carbon atoms in graphite layer are bonded strongly with each other. While two layers of graphite are weakly bonded to each other
So here two layers of graphite can easily slide over each other which is useful for the function of lubricants
So correct answer will be
Carbon atoms form strong bonds within each graphite layer but weak bonds between layers.
The half life of cobalt-60 is 5.3 years. If a certain rock currently contains 10.0g of cabals -60 how much cobalt-60 will remain in the rock after 21.2 years
A. 1.25g
B. 2.50g
C. 0.63g
D. 5.00g
T = half life of cobalt-60 = 5.3 years
λ = decay constant for cobalt-60 = ?
decay constant is given as
λ = 0.693/T
inserting the values
λ = 0.693/5.3 = 0.131
N₀ = initial amount of cobalt-60 = 10 g
t = time of decay = 21.2 years
N = final amount of cobalt-60 after time "t"
final amount of cobalt-60 after time "t" is given as
N = N₀ [tex]e^{-\lambda t}[/tex]
inserting the values
N = 10 [tex]e^{-(0.131) (21.2)}[/tex]
N = 10 [tex]e^{-(0.131) (21.2)}[/tex]
N = 10 x 0.0622 g
N = 0.63 g
hence
C. 0.63 g
In 1991 four English teenagers built an eletric car that could attain a speed of 30.0m/s. Suppose it takes 8.0s for this car to accelerate from 18.0m/s to 30.0m/s. What is the magnitude of the car's acceleration?
a=Δv/Δt=(30.0-18.0)/8.0=12.0/8.0=1.5 m/s²
Final answer:
The magnitude of the car's acceleration is calculated using the change in velocity over the time taken. With a change in velocity of 12.0 m/s over 8.0 seconds, the car's acceleration is 1.5 m/s².
Explanation:
To find the magnitude of the car's acceleration, we can use the formula for acceleration, which is the change in velocity (Δv) divided by the time (Δt) it takes for that change. In this case, the car's velocity increases from 18.0 m/s to 30.0 m/s over 8.0 seconds.
We calculate acceleration (a) as follows:
a = Δv / Δt
Δv = final velocity - initial velocity = 30.0 m/s - 18.0 m/s = 12.0 m/s
Δt = 8.0 s
Thus, a = 12.0 m/s / 8.0 s = 1.5 m/s².
The magnitude of the car's acceleration is 1.5 m/s².
The power in a lightbulb is given by the equation P- FR where /is the current flowing through the lightbulb and Ris the resistance of the lightbulb. What is the current in a circuit that has a resistance of 30.0 o and a power of 2.00 W?
A.) 15.0 A
B.) 3.87 A
C.) 0.258 A
D.) 0.067 A
(PLEASE HELP NEED ANSWER ASAP)
POWER OF CIRCUIT
P=VI
While,
VOLTAGE OF CIRCUIT
V=IR
THEN,
P=I^R
P/R=I^
2.00/30.0=I^
I=0.258A.
Answer:0.258
Explanation:
Calculate the momentum for a 0:2 kg rifle bullet traveling 300m/a
Given data
mass (m) = 0.2 Kg ,
velocity (v) =300 m/s ,
calculate momentum (p) = m × v
= 0.2 × 300
P = 60 Kg. m/s
Momentum of the bullet is 60 Kg. m/s..