Matter that emits no light at any wavelength is called DARK MATTER.
Answer:
Centripetal acceleration,

Explanation:
Centripetal acceleration:
Centripetal acceleration is the idea that any object moving in a circle, in something called circular motion, will have an acceleration vector pointed towards the center of that circle.
Centripetal means towards the center.
Examples of centripetal acceleration (acceleration pointing towards the center of rotation) include such situations as cars moving on the cicular part of the road.
An acceleration is a change in velocity.
Formula for Centripetal acceleration:

Given here,
Velocity = 4.5 m/s
radius = 7.7 m
To Find :

Solution:
We have,

Substituting given value in it we get

Centripetal acceleration,

Answer:
Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth. Motion energy is energy stored in the movement of objects. so the answer is thermal energy
B is the awser
good luck and hope it helps
Answer:
(a) 272.73 m
(b) 0.338 N/C
Explanation:
frequency, f = 1100 kHz = 1100 x 1000 Hz
E(t) = Eo Sin(2πft)
Eo = 0.62 N/C
(a) Velocity of light, c = 3 x 10^8 m/s
wavelength, λ = c / f = (3 x 10^8) / (1100000) = 272.73 m
Thus, the wavelength is 272.73 m.
(b) at t = 3.1 microsecond = 3.1 x 10^-6 s
E = Eo Sin (2 π ft)
E = 0.62 Sin (2 x 3.14 x 1100 x 10^3 x 3.1 x 10^-6)
E = 0.62 Sin (21.4148)
E = 0.62 x 0.5449 = 0.338 N/C
Thus, the electric field at t = 3.1 microsecond s 0.338 N/C.