Answer:
810 g
Explanation:
Mass is the product of density and volume:
m = ρV
m = (8.1 g/cm³)(100 cm³) = 810 g
The mass of the chunk is 810 grams.
Answer:
16.2 cents
Explanation:
Given that a homeowner consumes 260 kWh of energy in July when the family is on vacation most of the time.
Where Base monthly charge of $10.00. First 100 kWh per month at 16 cents/kWh. Next 200 kWh per month at 10 cents/kWh. Over 300 kWh per month at 6 cents/kWh.
For the first 100 kWh:
16 cent × 100 = 1600 cents = 16 dollars
Since 1 dollar = 100 cents
For the remaining energy:
260 - 100 = 160 kwh
10 cents × 160 = 1600 cents = 16 dollars
The total cost = 10 + 16 + 16 = 42 dollars
Note that the base monthly of 10 dollars is added.
The cost of 260 kWh of energy consumption in July is 42 dollars
To determine the average cost per kWh for the month of July, divide the total cost by the total energy consumed.
That is, 42 / 260 = 0.1615 dollars
Convert it to cents by multiplying the result by 100.
0.1615 × 100 = 16.15 cents
Approximately 16.2 cents
Can you be a bit more specific plz and that will let me identify the answer
Answer:
It has poor tensile strength despite having high compressive strength
Explanation:
Concrete exhibits high compressive strength when used. However, it has very low compressive strength. This is the reason why concrete is normally combined with steel to make a composite building material called reinforced concrete. The steel reinforces concrete hence increasing the tensile strength in RC buildings. The end composite is durable and fireproof. Generally, the main reason why concrete is not use on its own is due to its poor tensile strength.
Answer:
a) 1253 kJ
b) 714 kJ
c) 946 C
Explanation:
The thermal efficiency is given by this equation
η = L/Q1
Where
η: thermal efficiency
L: useful work
Q1: heat taken from the heat source
Rearranging:
Q1 = L/η
Replacing
Q1 = 539 / 0.43 = 1253 kJ
The first law of thermodynamics states that:
Q = L + ΔU
For a machine working in cycles ΔU is zero between homologous parts of the cycle.
Also we must remember that we count heat entering the system as positiv and heat leaving as negative.
We split the heat on the part that enters and the part that leaves.
Q1 + Q2 = L + 0
Q2 = L - Q1
Q2 = 539 - 1253 = -714 kJ
TO calculate a temperature for the heat sink we must consider this cycle as a Carnot cycle. Then we can use the thermal efficiency equation for the Carnot cycle, this one uses temperatures:
η = 1 - T2/T1
T2/T1 = 1 - η
T2 = (1 - η) * T1
The temperatures must be given in absolute scale (1453 C = 1180 K)
T2 = (1 - 0.43) * 1180 = 673 K
673 K = 946 C
