D) a car speeding up may i have brainliest hope this help
We use the following expression
T = 2*pi *sqrt(l/g)
Where T is the period of the pendulum
l is the length of the pendulum
and g the acceleration of gravity
We solve for l
l = [T/2*pi]² *g = [30s/2*pi]²* 9.8 [m/s²] = 223.413 m
The tower would need to be at least 223.413 m high
Intensity:
Decibels
Amplitude:
Meters
Frequency: Hertz
<u>Explanation:</u>
The Wave is not visible to eyes and they can easily propagate through vacuum. the average power travelling at a given period of time in a space is the intensity. Decibels is the measure of intensity. it is measured in the decibel scale. The wave's strength and the intensity gives the amplitude of wave. It is measured using meters.
The wave's amplitude and the energy has a direct proportionality. The number occurrence of wave cycles per second refers to the frequency of wave. it is measured in hertz. it is also measured as the number of cycles that occurs per second.
Answer:
3 m/s
Explanation:
Average Speed = 
Plug in the numbers, it will be (6m + 3m) divided by (2s + 1s), which is 9m/3s, which equals to 3m/s.
