The moment of inertia of a fly wheel is 0.2kgm2 which is initially stationary. A constant external torque 5Nm acts on the wheel. The work done by this torque during 10 seconds is

Question

The moment of inertia of a fly wheel is 0.2kgm2 which is initially stationary. A constant external torque 5Nm acts on the wheel. The work done by this torque during 10 seconds is (A) 1250 J (B) 2500 J (C) 5000 J (D) 6250 J

Tardigrade Admin · Accepted Answer

I=0.2kg m2 τ=5 Nm ωi=0 t=10 s we know α=(τ/I)=25 rad s-2 ∴ θ=(1/2)α t2=(1/2)(25)(100)=1250 ∴ W=τ θ=5(1250)=6250J

Q. The moment of inertia of a fly wheel is $0.2 k g m^{2}$ which is initially stationary. A constant external torque 5Nm acts on the wheel. The work done by this torque during 10 seconds is

1250 J

2500 J

5000 J

6250 J

$I = 0.2 k g m^{2}$
$τ = 5 N m$
$ω_{i} = 0$
$t = 10 s$
we know $α = \frac{τ}{I} = 25 r a d s^{- 2}$
$∴ θ = \frac{1}{2} α t^{2} = \frac{1}{2} (25) (100) = 1250$
$∴ W = τ θ = 5 (1250) = 6250 J$

Q. The moment of inertia of a fly wheel is 0.2kgm2 which is initially stationary. A constant external torque 5Nm acts on the wheel. The work done by this torque during 10 seconds is