Answer:
The amount of kilograms of ice at -20.0°C that must be dropped into the water to make the final temperature of the system 40.0°C = 0.0674 kg
Explanation:
Heat gained by ice in taking the total temperature to 40°C = Heat lost by the water
Total Heat gained by ice = Heat used by ice to move from -20°C to 0°C + Heat used to melt at 0°C + Heat used to reach 40°C from 0°C
To do this, we require the specific heat capacity of ice, latent heat of ice and the specific heat capacity of water. All will be obtained from literature.
Specific heat capacity of ice = Cᵢ = 2108 J/kg.°C
Latent heat of ice = L = 334000 J/kg
Specific heat capacity of water = C = 4186 J/kg.°C
Heat gained by ice in taking the total temperature to 40°C = mCᵢ ΔT + mL + mC ΔT = m(2108)(0 - (-20)) + m(334000) + m(4186)(40 - 0) = 42160m + 334000m + 167440m = 543600 m
Heat lost by water = mC ΔT = 0.25 (4186)(75 - 40) = 36627.5 J
543600 m = 36627.5
m = 0.0674 kg = 67.4 g of ice.
Answer:
d. Imaginary point through which the resultant force of gravity acts on an object
Explanation:
Gravity acting on all particle points of the object, no matter how small they are. As a combination, the center of gravity would denote a single point which substitutes for all the gravity forces on the object.
mass = 30kg
frictional force = coefficient of friction * (mass * g)
g = 9.8 m/s^2
So:
60N = x * 294 N
x = 60 N / 294 N = 0,2
Answer: State laws take precedence over UETA
Explanation: The UETA is an attempt to standardize acceptance of electronic documents and signatures, but state laws govern the use of these electronic items.
Answer:
W = y (b-a) / ab
Explanation:
Work is defined by the expression
W = ∫ F. dr
In this case the force is in the same direction of displacement, so the scalar product is reduced to the ordinary product
W = ∫ F dr
The expression of the strength left is
F = -y / x²
let's replace and integrate
W = ∫ (-y / x²) dx
W = -y (-1 / x)
We evaluate between the lower limit x = b + a to the upper limit x = 0 + a
W = -y (-1 / b + 1 / a)
W = y (b-a) / ab
where (b-a) is the distance traveled
