Question

If the L-shaped rod has a moment of inertia I=9kgm2, F1=12N, F2=27N, and again F3=0, how long a time t would it take for the object to move through 45∘ ( π/4 radians)? Assume that as the object starts to move, each force moves with the object so as to retain its initial angle relative to the object. Express the time in seconds to two significant figures.

Answer 1

Answer:

Time, t = 2.80seconds

Explanation:

Calculating net Torque, T

Torque(net)= F2(0.08m) - F1(0.03)

Torque(net) = (27×0.08)-(12×0.03)

Torque(net)= 2.16 - 0.36 =1.8N/m

Pi/4= Torque(net)/ Inertia

3.142/4= 1.8/9 = 0.2rad/s^2=a

Pi/4= 1/2 at^2

3.142/4=1/2×0.2 ×t^2

0.7855= 0.1 t^2

t = sqrt(0.7856/0.1)

t= sqrt(7.855)

t=2.80 seconds