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never [62]
3 years ago
13

Who invented the cellphone

Physics
2 answers:
wel3 years ago
7 0
Martin Cooper invented the cell phone
ad-work [718]3 years ago
7 0
Martin cooper is the one who invented cellphone
You might be interested in
Two objects have charges 2.0 C and 1.0 C. If the objects are placed 2 meters apart, what is the magnitude of the force that the
kondor19780726 [428]

Answer:

4.5\cdot 10^9 N

Explanation:

The electric force between two charged objects is given by:

F=k\frac{q_1 q_2}{r^2}

where:

k is the Coulomb's constant

q1 and q2 are the charges of the two objects

r is their separation

In this problem:

q1 = 2.0 C

q2 = 1.0 C

r = 2 m

So, the electric force is

F=(9\cdot 10^9 Nm^2C^{-2})\frac{(2.0 C)(1.0 C)}{(2 m)^2}=4.5\cdot 10^9 N

4 0
4 years ago
A sound wave has a frequency of 425 Hz. What is the period of this wave
Oduvanchick [21]

Answer: The time period of the given wave with frequency of 425 Hertz is 0.0023 seconds.

Explanation:

Frequency of the wave = 425 Hertz =425 sec^{-1}

\text{Time period}=\frac{1}{Frequency}

\text{Time period}==\frac{1}{425 sec^{-1}}=0.0023 sec

The time period of the given wave with frequency of 425 Hertz is 0.0023 seconds.

5 0
3 years ago
What is one disadvantage of sending information over long distances
shusha [124]

Answer:

A is the correct answer.

4 0
3 years ago
Read 2 more answers
A marble, a bowling ball, a basketball, and a baseball are all sitting on the top shelf of a display case. Which one has the gre
Katena32 [7]

Answer:

Bowling Ball

Explanation:

The potential energy depends on the factors: mass of the object and distance between the two objects. In this case the distance is between the ground and the balls. Here, the bowling ball is heaviest and its center of mass is farthest in comparison to other two balls. Thus, it has the greatest potential energy.

5 0
3 years ago
An electron accelerated from rest through a voltage of 780 v enters a region of constant magnetic field. part a part complete if
maxonik [38]
The electron is accelerated through a potential difference of \Delta V=780 V, so the kinetic energy gained by the electron is equal to its variation of electrical potential energy:
\frac{1}{2}mv^2 =  e \Delta V
where
m is the electron mass
v is the final speed of the electron
e is the electron charge
\Delta V is the potential difference

Re-arranging this equation, we can find the speed of the electron before entering the magnetic field:
v= \sqrt{ \frac{2 e \Delta V}{m} } = \sqrt{ \frac{2(1.6 \cdot 10^{-19}C)(780 V)}{9.1 \cdot 10^{-31} kg} }=1.66 \cdot 10^7 m/s


Now the electron enters the magnetic field. The Lorentz force provides the centripetal force that keeps the electron in circular orbit:
evB=m \frac{v^2}{r}
where B is the intensity of the magnetic field and r is the orbital radius. Since the radius is r=25 cm=0.25 m, we can re-arrange this equation to find B:
B= \frac{mv}{er}= \frac{(9.1 \cdot 10^{-31}kg)(1.66 \cdot 10^7 m/s)}{(1.6 \cdot 10^{-19}C)(0.25 m)} =3.8 \cdot 10^{-4} T
3 0
4 years ago
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