which statement below is FALSE? A Gravity acts on any object with mass. B The closer objects are, the stronger the gravitational
1 answer:
You might be interested in
Answer:
15.8 V
Explanation:
The relationship between capacitance and potential difference across a capacitor is:
where
q is the charge stored on the capacitor
C is the capacitance
V is the potential difference
Here we call C and V the initial capacitance and potential difference across the capacitor, so that the initial charge stored is q.
Later, a dielectric material is inserted between the two plates, so the capacitance changes according to
where k is the dielectric constant of the material. As a result, the potential difference will change (V'). Since the charge stored by the capacitor remains constant,
So we can combine the two equations:
and since we have
V = 71.0 V
k = 4.50
We find the new potential difference:
Answer:
350 F to 100 F it take approx 87.33 min
Explanation:
given data
oven = 350◦F
cooling rack = 70◦F
time = 30 min
cake = 200◦F
solution
we apply here Newtons law of cooling
= -k(T-Ta)
=
(T(t) -Ta)
= = -k(T-Ta)
-ky = -ky
T(t) -Ta = (To -Ta) T(t) = Ta+ (To -Ta)
put her value for time 30 min and T(t) = 200◦F and To =350◦F and Ta = 70◦F
so here
200 = 70 + ( 350 - 70 )
k = 0.025575
so here for T(t) = 100F
100 = 70 + ( 350 - 70 )
time = 87.33 min
so here 350 F to 100 F it take approx 87.33 min
Answer:
change in entropy is 1.44 kJ/ K
Explanation:
from steam tables
At 150 kPa
specific volume
Vf = 0.001053 m^3/kg
vg = 1.1594 m^3/kg
specific entropy values are
Sf = 1.4337 kJ/kg K
Sfg = 5.789 kJ/kg
initial specific volume is calculated as
FROM STEAM Table
at 200 kPa
specific volume
Vf = 0.001061 m^3/kg
vg = 0.88578 m^3/kg
specific entropy values are
Sf = 1.5302 kJ/kg K
Sfg = 5.5698 kJ/kg
constant volume so
Change in entropy
=3( 3.36035 - 2.88) = 1.44 kJ/kg