Which of the following describes what takes place when waves run into each other and become larger?

a. wave division
b. destructive interference
c. constructive interference
d. multiplication interference

We talk about Constructive Interference when two waves interfere and at the points where the two crests coincide, then the amplitudes of these waves are added together.

In other words:

It refers to the superposition of two or more waves with equal frequency, which when interfered create a new wave pattern with greater intensity (which is directly related to the amplitude).

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min