Plane water waves in a ripple tank pass through a narrow gap
in a barrier.
a) draw the appearance of the waves when the gap is much
larger than the wavelength of the water waves.
b) draw the appearance of the waves when the gap is the
same size as the wavelength of the water waves.
explain why designers must choose the size of a harbour
entrance carefully if boats moored there are to be in
calm water.

the gas collects in coils that then becomes a liquid that then flows through the coils inside the refrigerator

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

3. dark matter

empty space could also be a simple vacuum