Answer:
<u>because of the doppler effect</u>
Explanation:
<em>Remember</em>, the doppler effect refers to the changes in sound (frequency of sound) observed by a person who is in a position relative to the wave source.
In this example, we notice as the train comes closer to the boy, the sound becomes louder also increasing the pitch slightly, the doppler effect sets in when the train passes the boy because the boy notices a decrease in the pitch of the moving train.
We learn from the change in the observed sound of the train that the frequency of the sound is determined by the distance of the observer from the wave source.
In other words, the closer the source of the sound to the observer; the faster it travels to the observer, however, the farther it is; the lesser it is; the greater the sound heard.
Answer:
Increasing the mass and decreasing the distance between the two objects.
Explanation:
An increase in mass will cause them to have a stronger pull or gravity. A decrease of distance will make it easier for the objects to fall into each other because they would be further into the other objects area of influence.
By tightening a string you are actually putting more stress on the string you are giving it a new frequency that isn't natural.
Hope this helps
<span />
(A)energy lost in the lever due to friction
(C)
visual estimation of height of the beanbag
(E)position of the fulcrum for the lever affecting transfer of energy
Answer:
Two equal and opposite parallel forces not acting along the same line, form a couple. A couple is always needed to produce the rotation.
For example, turning a key in a lock and turning a steering wheel.
