Question

An electric motor rotating a workshop grinding wheel at 1.06 102 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.10 rad/s2. (a) How long does it take the grinding wheel to stop

Answer 1

Answer:

t = 106π / 30*2.1

Explanation:

$w_{i} = 1.06*10^{2}$    => 106

    => 106 x 2π/60

    => 106/30π

∝ = -2.1 rad/sec²

$w_{f}$ => 0

$w_{f}$ = $w_{i}$ + ∝t

∴ ($w_{f}$ - $w_{i}$) / ∝ = t

t = 106π / 30*2.1