Answer:

Explanation:
The electrostatic potential energy for pair of charge is given by
U=1/4π∈₀×(q₁q₂/r)
Hence for a system of three charges the electrostatic potential energy can be found by adding up the potential energy for all possible pairs or charges.For three equal charges on the corners of an equilateral triangle,the electrostatic potential energy is given by:
U=1/4π∈₀×(q²/r)+1/4π∈₀×(q²/r)+1/4π∈₀×(q²/r)
U=3×1/4π∈₀×(q²/r)
Substitute given values
So
Gravitational potential energy = mgh or mass times acceleration due to gravity times the height
Here the mass is 0.25kg, the height is 10m, and gravity is 9.8m/s^2 so...
GPE = (0.25)(10)(9.8)
GPE = 24.5 J
Explanation:
the velocity graph of a ball mass 20mg moving along a straight line
Answer:
about 14.7°
Explanation:
The formula for the angle of the first minimum is ...
sin(θ) = λ/a
where θ is the angle relative to the door centerline, λ is the wavelength of the sound, and "a" is the width of the door.
The wavelength of the sound is the speed of sound divided by the frequency:
λ = (340 m/s)/(1300 Hz) ≈ 0.261538 m
Then the angle of interest is ...
θ = arcsin(0.261538/1.03) ≈ 14.7°
At an angle of about 14.7°, someone outside the room will hear no sound.