The moon's gravitational pull on Earth causes water to bulge on two sides of the Earth(#3)
https://scijinks.gov/tides/
Yes, C is correct. It self explains itself as we know light travels through a vacuum ( doesn't need a medium) and light is a type of electromagnetic wave.
Velocity, va2 = 10.5 ft/s
<u>Explanation:</u>
From the figure:
Length of the cable = Sa + 2Sb = l
∴ vₐ = -2vb
Applying the principle of Impulse and momentum in x-direction

Limit is t1 to t2
-(1)
Applying the principle of Impulse and momentum in y-direction

Limit is t1 to t2
-(2)
Solving equation (1) and (2), we obtain
T = 1.6lb
va2 = 10.5 ft/s