Newton's first law of motion says something like "An object remains
in constant, uniform motion until acted on by an external force".
Constant uniform motion means no change in speed or direction.
If an object changes from rest to motion, that's definitely a change
of speed. So it doesn't remain in the state of constant uniform
motion (none) that it had when it was at rest, and that tells us
that an external force must have acted on it.
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
Answer:
did you get it done if not lmk I will help you out tomorrow when I get up