(a) The frequency observed by the passenger on the east-bound train when they are 1000 m apart is 675.5 Hz.
(b) After 10 seconds, the frequency observed by the passenger on the east-bound train will be greater than the frequency observed when they are 1000 m apart.
<h3>Observed frequency</h3>
The frequency observed by the passenger on east-bound train is calculated by applying Doppler shift formula.
where;
- f is observed frequency
- f₀ is original frequency or source frequency
- v is speed of sound
- v₀ is speed of observer (positive when moving towards source)
- vs is source frequency (negative when moving towards observer)
<h3>when the two trains are 1000 m apart</h3>
The frequency observed by the passenger increases with decrease in distance between the two trains.
Thus, after 10 seconds, the frequency observed by the passenger on the east-bound train will be greater than the frequency observed when they are 1000 m apart.
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The density of the glass can be determined using the formula:
- Density of the glass = (Mf - Mi)/20 cm³
<h3>What is density?</h3>
Density is defined as the ratio of mass and volume of a substance.
The mass of the glass = Final mass of beaker - initial mass of beaker (Mf - Mi)
The initial mass of the beaker is not given.
Volume of the glass marble = 20 cm³
Density of the glass = (Mf - Mi)/20 cm³
Therefore, the density of the glass is determined from the ratio of the mass and volume of the glass.
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(4) a metal sphere with a charge of 1.0 × 10^−9 C <span>moved through a potential difference of 4.0 V would undergo the greatest change in electrical energy from the list. </span>
Answer:
The velocity (
) of the wave is 3.08 
.
Explanation:
According to the figure, the distance (
) between a trough and its adjacent crest is 
. Also the wavelength (
) of the wave is 
. Pepe and Alfredo count 11 crests to pass the raft in 
= 21.5 s.
So, the time period (
) of oscillation of the wave is
So, the velocity (
) of the wave is
