Answer:
2.62seconds
Explanation:
Speed is defined as the ratio of the distance covered by a body with respect to time.
Speed v = Distance (s)/Time (t)
For a traveling sound wave, the distance between the source of a sound and the reflector is '2S'.
Speed v = 2 × distance (S)/Time (T)
V = 2S/t
2S = vt
Given speed of the wave = 342m/s
Distance covered = 450m
t = 2S/v
t = (2×450)/343
t = 900/343
t = 2.62seconds
It will take him 2.62seconds for him to hear his own voice echo off of the wall.
Physical and chemical changes are similar because matter experiences a change in state while undergoing either change.
I attached a free body diagram for a better understanding of this problem.
We start making summation of Moments in A,



Then we make a summation of Forces in Y,



At the end we calculate the angle with the sin.


Answer: (a)part:545nm multiply by 0.440m=239.8JEWELS(J)
(B):1/2MULTIPLY BY MVSQUARE(APPLY THE FORMULA OF KINETIC ENERGY)REARANGE THE FORMULA,V=2.13MS
Explanation:
SO FOR PART A, IN ORDER TO CALCULATE THE WORK DONE YOUR SUPPOSE TO APPLY THE FORMULA FORCE MULTIPLY BY DISTANCE WHICH IS THE FORMULA FOR WORK DONE,IN THIS SCENARIO YOU HAD A FORCE OF 545NM AND A DISANCE OF 0.440,SO I ORDER TO FIND THE WORK DONE WE MULTIPLIED THEM BOTHE ACCORDING TO THE FORMULA AND GOT THE ANSWER.
FOR PARTB,I JUST SIMPLY APPLIED THE FORMULA FOR KINETIC ENERGY AND SIMPLY REARRANGED IT IN ORDER TO FIND THE VELOCITY.I MADE V THE SUBJECT OF THE FORMULA.