00:01
And this problem, we're given the same setup of pulleys and three blocks as in the previous problem.
00:06
So we have the same constraints that 3va plus 4vb plus vc is zero and likewise for the accelerations.
00:16
And this time we're told that block b moves downward with a constant velocity.
00:23
And so the acceleration of b is zero.
00:26
Right here.
00:28
So the constant velocity is 20 millimeters per second.
00:33
So i've said down is positive, just like in the previous problem.
00:38
And we're told that block a is moving upwards with the constant acceleration and its velocity is 30 millimeters per second.
00:48
And it's moving upwards, so that is and at t equals zero, so that is minus 30 millimeters per second.
00:56
So v and v and a not is finest 30 millimeters per second.
01:02
And let's see here, so at t equals three seconds, slider block c has moved 57 millimeters.
01:13
So that's, we'll call that t2.
01:20
So t2 is three seconds...