Question

A grinding wheel of mass 5.0kg and diameter 0.4m is rotating with an angular speed of 2 rev s-1.calculate the torque which will increase its angular speed to 8 revolution per second in 2s

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Answer 1

Answer:

Torque required = 1.88 Nm

Explanation:

radius of wheel r = 0.2 m

M.O.I of wheel about its centre I = Mr²/2

                                                      = 5 x 0.04/2

                                                      = 0.1 kg m²

Angular accln α = (ω₂- ω₁)/t

                          = 2π(N₂ -N₁) /t

                           = 2π(8-2)/2

                           = 6π rad/s²

Torque τ = Iα = 0.1 x 6π = 0.6π N m = 1.88 Nm