Hello,
It's D! hope I helped.
Answer:
Explanation:
Person A's velocity relative to the train is 0. Therefore, the pitch of the horn will not change.
Answer:
For the first one c is the answer
For the second one c is also the answer
For the third one is b
Explanation:
I took that
Forces that are equal in size but opposite in direction and do not cause a change in an object's movement are called balanced forces.
forces that aren't equal in size and do cause a change in movement (what it seems like you're asking for) are called UNBALANCED FORCES
so answer (in case that wasn't clear, as I'm tired) : unbalanced forces
Let the height where we are trapped is H
now to find the time to reach the key at the bottom is given as

now we have


now if the speed of sound is considered to be 340 m/s then time taken by the sound to reach at the top is given as

now the total time is given as

now by solving above equation we have
H = 48 m
now height of one floor is 3 m
so our position must be
