I think it occurs whenever waves come together so that they are in phase with each other.
We have that F=ma from the 2nd Newton law where F is the force, m is the mass and a is the acceleration. Suppose we have that F' is the new force and m' is the new mass. Then, we have that a'=F'/m' still, by rearranging Newton's law. We are given that F'=2F and m'=m/2. Hence,

But now, we have from F=ma, that a=F/m and we are given that a=1m/s^2.
We can substitute thus, a'=4a=4*1m/s^2=4m/s^2.
Answer:
W= 4.89 KJ
Explanation:
Lets take
temperature of hot water T₁ = 100⁰C
T₁ = 373 K
Temperature of cold ice T₂= 0⁰C
T₂ = 273 K
The latent heat of ice LH= 334 KJ
The heat rejected by the engine Q= m .LH
Q₂= 0.04 x 334
Q₂= 13.36 KJ
Heat gain by engine = Q₁
For Carnot engine


Q₁ = 18.25 KJ
The work W= Q₁ - Q₂
W= 18.25 - 13.36 KJ
W= 4.89 KJ
Answer;
1 hectare meter is equal to 10000 cubic meter.
Here when car in front of us applied brakes then it is slowing down due to frictional force on it
So here we can say that friction force on the car front of our car is given as

So the acceleration of car due to friction is given as



now it is given that


so here we have


so the car will accelerate due to brakes by a = - 8.52 m/s^2