Refer to Exhibit 9-2 below.Exhibit 9-2 The figure below shows a graph of angular velocity versus time for a man cycling around a circular track. What is his average angular acceleration, in rad/s2, in the period from t = 6 min to t = 8 min?
A)0
B) $-\frac{\pi}{90}$
C) $-\frac{\pi}{30}$
D) $+\frac{\pi}{30}$
E) $+\frac{\pi}{90}$

Question

Refer to Exhibit 9-2 below.Exhibit 9-2 The figure below shows a graph of angular velocity versus time for a man cycling around a circular track.  What is his average angular acceleration, in rad/s2, in the period from t = 6 min to t = 8 min?
A)0 
B) $-\frac{\pi}{90}$ 
C) $-\frac{\pi}{30}$ 
D) $+\frac{\pi}{30}$ 
E) $+\frac{\pi}{90}$

Quizplus · Accepted Answer

To find the average angular acceleration, we need to use the equation for angular acceleration:
α = Δω/Δt
where Δω is the change in angular velocity and Δt is the change in time. From the graph, we can see that the angular velocity changes from about 0.52 rad/s to about 1.56 rad/s between t = 6 min and t = 8 min, which is a change of:
Δω = (1.56 rad/s) - (0.52 rad/s) = 1.04 rad/s
The time interval is:
Δt = (8 min) - (6 min) = 2 min = 120 s
Thus, the average angular acceleration is:
α = Δω/Δt = (1.04 rad/s)/(120 s) = 0.00867 rad/s^2
This is closest to answer choice C: 11eb8b15_74ff_d7af_8952_19dc0e7129d1_TB8845_11.

Refer to Exhibit 9-2 Below −π90-\frac{\pi}{90}−90π​ C) −π30-\frac{\pi}{30}−30π​ D) +π30+\frac{\pi}{30}+30π​ E) +π90+\frac{\pi}{90}+90π​

Refer to Exhibit 9-2 Below $-\frac{\pi}{90}$ C) $-\frac{\pi}{30}$ D) $+\frac{\pi}{30}$ E) $+\frac{\pi}{90}$