A drum rotates around its central axis at an angular velocity of 14.4 rad/s. If the drum then slows at a constant rate of 8.02 rad/s^2, (a) how much time does it take and (b) through what angle does it rotate in coming to rest?

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Answer 1 · 2015-12-03T07:29:26

$(a)$ $(a)$

$1.8 s$ $1.8"s"$

$(b)$ $(b)$

$12.92$ $12.92$ $rad$ $" rad"$

I will use the equations of motion:

(a)

$v = u + a t$ $v=u+at$

$:.0=14.4-8.02t$

$:.t=14.4/8.02=1.8"s"$

(b)

The angle through which it rotates is analogous to distance so we can use:

$s=ut+1/2at^2$

$:.s=14.4xx1.8-1/2xx8.02xx1.8^2$

$s=12.92$ $"rad"$