Answer:
P = 5280 W
Explanation:
The conductivity of the materials determines that heat flows from the hot part to the cold part, the equation for thermal conductivity transfer is
P = Q / t = k A (
-
) / L
Where k is the thermal conductivity of the glass 0.8 W / ºC, A the area of the window, T the temperature and L is glass thickness
Let's calculate the window area
A = l * a
A = 2.0 1.0
A = 2.0 m²
Let's replace
L = 0.5 cm (1 m / 100 cm) = 0.005 m
P = 0.8 2 (20.5 - 4) / 0.005
P = 5280 W
W = Fd = 4(2100) = 8400 J
So the answer is A) 8400 J
I was just rewriting my notes on the work lesson I did in class today, so I saw this question at the perfect time!! :)
Hope it helps!! :)
Answer:
Explanation:
According to Faraday-Newmann-Lenz, the induced emf in the loop is given by:
(1)
where 
is the rate of variation of the magnetic flux through the loop.
We know that the magnetic flux through the loop is given by
where B is the magnetic field and A is the area of the loop. Since the magnetic field is constant, we can write the variation of flux as
So eq.(1) becomes
and the problem gives us:
is the magnetic field
is the rate at which the area changes
Substituting into the equation, we find
Maybe the picture helps. The blue block represents the cart with a mass of 3 kg. The person(black block) is pulling the cart to the right with a force F so that the acceleration a is 2 m/s². According to Newton's 2nd law: F = m*a.
Answer:
(A) 0.004 m^3
(B) 48.11 K
Explanation:
Work, W = 2100 J
Pressure, P = 1 x 10^5 Pa
V2 = 0.025 m^3
(A) let the initial volume of the gas is V1.
W = P (V2 - V1)
2100 = 1 x 10^5 (0.025 - V1)
0021 = 0.025 - V1
V1 = 0.025 - 0.021
V1 = 0.004 m^3
Thus, the initial volume of the gas is 0.004 m^3.
(B) Let the temperature of the gas is T
Use ideal gas equation
P1 x V1 = n x R T
1 x 10^5 x 0.004 = 1 x 8.314 x T
T = 48.11 K
Thus, the initial temperature of the gas is 48.11 K.
