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Pavel [41]
3 years ago
8

Despite the advent of digital television, some viewers still use "rabbit ears" atop their sets instead of purchasing cable telev

ision service or satellite dishes.
Certain orientations of the receiving antenna on a television set give better reception than others. Furthermore, the best orientation varies from station to station.
Explain.
Physics
1 answer:
Maslowich3 years ago
7 0

Answer:

This is due to difference in bandwidths of different stations, and the inability of the bunny ear to accommodate distant bandwidths most times at the same time.

Explanation:

Bunny ears are a simple half-wave dipole antenna used to receive VHF television bands. It is constructed of two telescoping rods attached to a base, these rods extend out to about 1 meter length, and are collapsible when not in use. For the best reception the rods should be adjusted to be a little less than 1/4 wavelength at the frequency of the television channel being received and bandwidth of different station differs one frone another, so adjustment has to be made sometimes in order to get reception from other stations. Thankfully, the dipole has a wide bandwidth, so most times, adequate reception is achieved without having to adjust the length of the bunny ear.

The half wave dipole of a bunny ear has a low gain of about 2.14 dBi; which means it is not as directional and sensitive to distant stations as a large rooftop antenna, but its wide angle reception pattern may allow it to receive several stations located in different directions without requiring readjustment when the channel is changed. Sometime an adjustment of the rods is necessary.

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The ammonia molecule (NH3) has a dipole moment of 5.0×10?30C?m. Ammonia molecules in the gas phase are placed in a uniform elect
Neko [114]

Question (continuation)

(a) What is the change in electric potential energy when the dipole moment of a molecule changes its orientation with respect to E S from parallel to perpendicular?

(b) At what absolute temperature T is the average translational kinetic energy 3/2kT of a molecule equal to the change in potential energy calculated in part (a)?

Answer:

a. 9.0 * 10^-24 Joules

b. 0.44K

Explanation:

Given

Let p = dipole moment = 5.0 * 10^-30 Cm

Let E = Magnitude = 1.8 * 10^6 N/m

a.

The charge in electric potential = Final Charge - Initial Charge

Initial Charge = Potential Energy

Initial Energy = -pE cosФ where Ф = 0

So, initial Energy = - 5.0 * 10^-30 * 1.8 * 10^6

Initial Energy = -9 * 10^-24 Joules

Final Energy = 0

Charge = 0 - (-9.0 * 10^-24)

Charge = 9.0 * 10^-24 Joules

b.

Absolute Temperature

Change in Kinetic Energy = Change in Potential Energy = 9.0 * 10^-24

Change in Kinetic Energy = 3/2kT where k is Steven-Boltzmann constant = 1.38 * 10^-23

So,

9.0 * 10^-24 = 3/2 * 1.38 * 10^-23 * T

T = (9.0 * 10^-24 * 2)/(3 * 1.38 * 10^-23)

T = (18 * 10^-24)/(4.14 * 10^-23)

T = 0.44K

6 0
3 years ago
What is the acceleration of the the object during the first 4 seconds?
AVprozaik [17]

Answer:

Velocity (m/s) over time (s) graph

Velocity (m/s) over time (s) graph

We could write out our average acceleration as:

a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t

a = (15 m/s - 0 m/s) / 0.2 seconds

a = 15 m/s / 0.2 seconds

a = 75 m/s / second

Explanation:

What this formula is telling us is that if we know the acceleration of an object, and the ... we can plug in our acceleration of 12.5 m/s2 for a, and 4 seconds for t.

Velocity (m/s) over time (s) graph

Velocity (m/s) over time (s) graph

We could write out our average acceleration as:

a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t

a = (15 m/s - 0 m/s) / 0.2 seconds

a = 15 m/s / 0.2 seconds

a = 75 m/s / second

6 0
3 years ago
What's the value of 1,152 Btu in joules? A. 1,964,445 J B. 2,485,664 J C. 987,875 J D. 1,215,360 J
OLga [1]

Answer: Option (d) is correct.

Explanation:

Given,  1,152 British thermal units

1 British thermal unit = 1055.06 joules

So, in 1,152 British thermal units there will be :

1152\times 1055.06 Joules=1215429.12 Joules=1.21542912\times 10^{8} Joules

Hence, from the given options the closest answer is of option (d). So, option (d) is correct.

4 0
3 years ago
Read 2 more answers
A Red Rider bb gun uses the energy in a compressed spring to provide the kinetic energy for propelling a small pellet of mass 0.
Kay [80]

Answer:

a.6.5025 J

b.6.5025 J

Explanation:

We are given that

Mass of pellet,m=0.27 g=0.27\times 10^{-3} kg

1 kg=1000 g

Spring constant,k=1800 N/m

x=8.5 cm=8.5\times 10^{-2} m

1m=100 cm

a.Potential energy stored in the compressed spring  is given by

P.E=\frac{1}{2}kx^2

P.E=\frac{1}{2}(1800)(8.5\times 10^{-2})^2

P.E=6.5025 J

b.By using law of conservation of energy

P.E of spring=K.E of the pellet

K.E of the pellet=6.5025 J

6 0
3 years ago
The rate (in cubic feet per hour) that a spherical snowball melts is proportional to the snowball's volume raised to the 2/3 pow
Darina [25.2K]

Answer:

A 3 feet radius snowball will melt in 54 hours.

Explanation:

As we can assume that the rate of  snowball takes to melt is proportional to the surface area, then the rate for a 3 feet radius will be:

T= A(3 ft)/A(1 ft) * 6 hr

A is the area of the snowballs. For a spherical geometry is computing as:

A=4.pi.R^2

Then dividing the areas:

A(3 feet)/A(1 foot) = (4 pi (3 ft)^2)/(4 pi (1 ft)^2) =  (36pi ft^2)/(4pi ft^2)= 9

Finally, the rate for the 3 feet radius snowball is:

T= 9 * 6 hr = 54 hr

6 0
3 years ago
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