Answer:
E = 13.2 kWh
, Cost = $ 10.8
Explanation:
We can look for the consumed energy from the expression of the power
P = W / t
The work is equal to the variation of the kinetic energy, for which
P = E / t
E = P t
look for the energy consumed in one day and multiply by the days of the month in the month
E = 110 4 30
E = 13200 W h
E = 13.2 kWh
the cost of this energy is
Cost = 0.9 12
Cost = $ 10.8
Answer:
D) directly, inversely
Explanation:
The energy of a photon of light is directly proportional to its frequency and inversely proportional to its wavelength.
Frequency is the number of waves that passes through a point per unit of time.
Wavelength is the is the distance between successive crests or troughs on a wave.
Mathematically, frequency is related to wavelength and velocity using;
Energy = h x f
where h is the Planck's constant
f is the frequency
Since c = f ∧
where f is the frequency of the wave
∧ is the wavelength of the wave
c is the speed of light
So;
f = c/∧
Therefore;
E = 
From the equation, we see an inverse relationship between E and wavelength and a direct one with frequency.
Explanation:
Young' modulus is the ratio of normal stress to the longitudinal strain. Mathematically, it is given by :
Normal stress is given by force per unit area. Longitudinal strain is the change in length per unit original length.
The mathematical definition of Young's modulus is given by :
..........(1)
Where
is the change in length
F is the force
A is the area of cross section
So, the Young's modulus refers to the change in length of the object. Hence, the correct option is (b) "length".
Answer:
solution:
to find the speed of a jogger use the following relation:
V
=
d
x
/d
t
=
7.5
×m
i
/
h
r
...........................(
1
)
in Above equation in x and t. Separating the variables and integrating,
∫
d
x
/7.5
×=
∫
d
t
+
C
or
−
4.7619
=
t
+
C
Here C =constant of integration.
x
=
0 at t
=
0
, we get: C
=
−
4.7619
now we have the relation to find the position and time for the jogger as:
−
4.7619 =
t
−
4.7619
.
.
.
.
.
.
.
.
.
(
2
)
Here
x is measured in miles and t in hours.
(a) To find the distance the jogger has run in 1 hr, we set t=1 in equation (2),
to get:
= −
4.7619
=
1
−
4.7619
= −
3.7619
or x
=
7.15
m
i
l
e
s
(b) To find the jogger's acceleration in m
i
l
/
differentiate
equation (1) with respect to time.
we have to eliminate x from the equation (1) using equation (2).
Eliminating x we get:
v
=
7.5×
Now differentiating above equation w.r.t time we get:
a
=
d
v/
d
t
=
−
0.675
/
At
t
=
0
the joggers acceleration is :
a
=
−
0.675
m
i
l
/
=
−
4.34
×
f
t
/
(c) required time for the jogger to run 6 miles is obtained by setting
x
=
6 in equation (2). We get:
−
4.7619
(
1
−
(
0.04
×
6 )
)^
7
/
10=
t
−
4.7619
or
t
=
0.832
h
r
s