A wave with a frequency of 80 Hz travels through rubber with a wavelength of 7.0 m. What is the velocity of the wave?
1 answer:
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Answer:
Q= 722.5 *10⁻¹² C
Explanation:
Conceptual analysis
For a parallel plate capacitor, we can use the following formula :
E= (Q) /(ϵ₀*A) Formula (1)
Where:
E: electric field between the plates ( N/C)
Q: Charge of the plates (C)
ϵo : vacuum permittivity ( C²/ N.m²)
A : area oh the plates (m²)
Known data
A = 1.2 m²
E= 68 N/C
ϵo= 8.8542*10⁻¹² ( C²/ N.m²)
Problem development
We apply the formula (1) :
Q= (68) (8.8542*10⁻¹²)(1.2)
Q= 722.5 *10⁻¹² C
Answer:
initial: 1654.6 J, final: 0 J, change: -1654.6 J
Explanation:
The length of the slide is
L = 8.80 ft = 2.68 m
So the height of the child when he is at the top of the slide is (with respect to the ground)
The potential energy of the child at the top is given by:
where
m = 63.0 kg is the mass of the child
g = 9.8 m/s^2 is the acceleration due to gravity
h = 1.13 m
Substituting,
At the bottom instead, the height is zero:
h = 0
So the potential energy is also zero: U = 0 J.
This means that the change in potential energy as the child slides down is