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Solnce55 [7]
3 years ago
8

Help!! Thank You!! Potassium has 19 protons. How many electrons does a neutral potassium atom have?

Physics
2 answers:
fredd [130]3 years ago
8 0
A neutral atom... no matter what the element... has the same number of protons and electrons. In this case, 19 electrons are needed.
Alisiya [41]3 years ago
7 0
19, because the number of protons and electrons are the same!
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Estimate the theoretical fracture strength of a brittle material if it is known that fracture occurs by the propagation of an el
julia-pushkina [17]
The solution as per the attached photo.

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4 years ago
“How bright would the sun appear to an observer on Earth if the sun were four times farther from Earth than it actually is? Expr
Alenkasestr [34]

Like a lot of other things, (gravity, sound, electrostatic force), brightness also decreases as the square of the distance.

When the source moves to a new position that's 4 times as far away, its apparent brightness becomes (1/4^2) its original value.

That's 1/16 .

4 0
4 years ago
A physics professor uses an air-track cart of mass m to compress a spring of constant k by an amount x from its equilibrium leng
zhenek [66]

Answer:

        v = √k/m    x

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starting point. Fully compressed spring

        Em₀ = K_{e} = ½ k x²

final point. Cart after leaving the spring

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6 0
4 years ago
The instant before a tennis racquet hits a 0.057 kg tennis ball, the velocity of the ball is 55 m/s west. The instant after
Wewaii [24]

Answer: 6700m/s^2 E

Explanation:

Given the following :

Velocity of ball before being hit by a racquet = initial velocity(u) = 55m/s W

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Time of contact between ball and racquet (t) = 1.5 × 10^-2

The acceleration of a body is the change in Velocity of a body with time. It given by:

Acceleration (a) = [final Velocity(v) - initial velocity(u)] / time(t)

The westward direction is towards the left and thus Velocity takes a negative value, similarly, if it's towards the right, Velocity takes a positive value.

Therefore,

a = [45 - (-55)] / 1.5×10^-2

a = [45 + 55] / 0.015

a = 100 / 0.015

a = 6666.6666 m/s^2

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Since the value of acceleration is positive, the direction is towards the East (acceleration is in the direction of the ball's final Velocity).

5 0
3 years ago
A 0.40-μF capacitor is connected to a 5.0-V battery. How much charge is on each plate of the capacitor? Express your answer usin
weqwewe [10]

Answer:

Q=2.0\times10^{-6}C

Explanation:

The equation of charge on the capacitor given its capacitance and a voltage applied to it is Q=CV.

Our capacitance is expressed in <em>microfarads</em>, where micro stands for \times10^{-6}, so in S.I. we sill have:

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Where the results has been expresed with <em>two significant figures</em>.

7 0
3 years ago
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