Let's take two balls, each of radius 0.1 meters and charge them each to 3 microCoulombs. Then, let's put them on a flat surface
1 answer:
Explanation:
First, we will calculate the electric potential energy of two charges at a distance R as follows.
R = 2r
=
= 0.2 m
where, R = separation between center's of both Q's. Hence, the potential energy will be calculated as follows.
U =
=
= 0.081 J
As, both the charges are coming towards each other with the same energy so there will occur equal sharing of electric potential energy between these two charges.
Therefore, when these charges touch each other then they used to posses maximum kinetic energy, that is, .
Hence, K.E =
=
= 0.0405 J
Now, we will calculate the speed of balls as follows.
V =
=
= 0.142 m/s
Therefore, we can conclude that final speed of one of the balls is 0.142 m/s.
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Answer:
20m
6.9s
Explanation:
The vertical velocity of the ball is 20m/s. We can calculate the kinetic energy which gets transferred to potential energy once it gets to the top.
we can subtitute v = 20m/s and g = 10m/s2
So the ball could go 20m high from the child hand, or 120m fro the bottom of the cliff.
The time it takes for the ball to travels to the top is the time it takes for it to decelerate from 20m/s to 0m/s with gravitational deceleration g = 10m/s2
t = v / g = 20 / 10 = 2s
Then the ball will start accelerating down ward with a constant acceleration of g = 10m/s. In order to cover distance d of 120m from the top to the bottom of the cliff
So the total time it takes is 4.9 + 2 = 6.9s
Answer:
The power of the distance is -1.
Explanation:
The equation for the electric potential of a point charge is given by
where V is the electric potential, k is Coulomb's constant (it has a value of with units
), q is the electric charge of the small charge and r is the distance from the charge.
Now, the power of a number is how many times we multiply that number by itself; we see r appears only once in the equation. So we know the power is 1. But we can see in the equation that k and q are divided by r, which means r is the denominator. This means the power of r is negative (-).
Therefore, the power of r is -1.
Answer:
The work function ϕ of the metal = 53.4196 x 10⁻¹⁶ J
Explanation:
When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.
The relationship between the maximum kinetic energy () of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:
= h(f − f₀)
= hf - hf₀
E is the energy of the absorbed photons: E = hf
ϕ is the work function of the surface: ϕ = hf₀
= E - ϕ
Frequency f = 8.12×10¹⁸ Hz
Maximum kinetic energy = 4.16×10⁻¹⁷ J
Speed of light c = 3 x 10⁸ m/s
Planck's constant h = 6.63 × 10⁻³⁴ Js
E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸
E = 53.8356 x 10⁻¹⁶ J
from = E - ϕ ;
ϕ = E -
ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷
ϕ = 53.4196 x 10⁻¹⁶ J
The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J