What is the answer to question 4

diffraction

Explanation: reflection wouldn't make sense because it's not reflecting off of anything and same with refraction and absorptions.

In order to make it all the way from the opening to the detector, a wave has to travel through air, glass, water, plastic, and vacuum.

-- The siren and the tuning fork are sounds.

-- Sound cannot travel through vacuum.

-- That knocks out choices B, C, and D.

The answer is A.

Note:  Making a big exception here.  We don't do test questions on That would be cheating. Don't let me catch you doing it again.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s