To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as,

Here,
= Frequency of Source
= Speed of sound
f = Frequency heard before slowing down
f' = Frequency heard after slowing down
v = Speed of the train before slowing down
So if the speed of the train after slowing down will be v/2, we can do a system equation of 2x2 at the two moments, then,
The first equation is,



Now the second expression will be,



Dividing the two expression we have,

Solving for v, we have,

Therefore the speed of the train before and after slowing down is 22.12m/s
True
Because I know lol they make u type so much
Answer:
B) 350 kg m/s
Explanation:
momentum or p is given by the equation p= mxv
We have the mass and velocity so we can use the equation directly
p= 72kg x 4.9 m/s
p= 352.8 kg m/s
Answer:
Aristotle
Explanation:
Aristotle would describe an airplane as "Earthen metal infused with Air and propelled by elemental Fire".
Their presence spread in to the Renaissance from the Antiquity and Early medieval Ages, and was not consistently displaced until the Inquisition and philosophies such as classical physics.Aristotle's views on biblical theory were influenced by physical science. Many of the zoological findings of Aristotle found in his physiology, such as on the octopus ' hectocotyl (reproductive) head, remained incredible until the 19th century.