What type of interference results in beats?
constructive
destructive
negligible
interference is not involved in the creation of beats

constructive

Explanation:

Two waves having slightly different frequencies when interfere constructively produce beats. Superposition of these two waves results in addition of amplitudes of the two waves. The amplitude of the resultant wave vibrates or beats.

Beat frequency is given by the absolute difference between the frequencies of the two waves.

b = |f₂ - f₁| = f₂ - f₁ or f₂ + f₁

the answer is b

explanation:

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