Question

                

                    Your engineering team has been assigned the task of measuring the properties of a new jet-engine turbine. You've previously determined that the turbine's                     moment of inertia is 2.6 kg?m2. The next job is to measure the frictional torque of                     the bearings. Your plan is to run the turbine up to several different initial predetermined rotation speeds, ?i, cut the power, and time                     how long it takes the turbine to reduce its rotation speed by 50% in each case. Your                     data are as follows:
                

                

                    
                

                

                    1. Graphing either t versus ?i or ?i versus t gives a straight line. In the graph shown, we chose to plot t on the vertical axis and ?i on the                     horizontal axis because Newton

Answer 1

so we know w0/2 = w0 + alpha t

-w0/2 = alpha t

t = - w0/2 alpha

so slope = -1/2 alpha

alpha = -1/(2*0.121)

torque = alpha I = 2.6*1/(2*0.121)= 10.74 Nm

Answer 2

about 11 N*m

get average rate change of alpha by 1/(2*0.121)=4.13 rad/s and get torque by 4.13*2.6=10.7N*m