A wheel is rotating about an axis that is in the z-direction. The angular velocity ?z is - 6.00 rad/s at t = 0, increases linearly with time, and is + 4.00 rad/s at t = 7.00 s. We have taken counterclockwise rotation to be positive. (a) Is the angular acceleration during this time interval positive or negative? (b) During what time interval is the speed of the wheel increasing? Decreasing? (c) What is the angular displacement of the wheel at t = 7.00 s?

Solution 8E The angular velocity about the z axis at time t = 0 was, Zt = 0) = 6 rad/s. At a later time, t = 7 s, (t = 7) = 4 rad/s Z a)Angular acceleration is, fi 4(6) = = 10 = 1.428 rad / s 2 f i 70 7 It is positive. b) First the speed decreases as the wheelâ€™s angular velocity is approaching from -6 rad/s to zero. Then it would increase when the angular velocity approaches to 4 rad/s from zero. So, we will consider for the 2nd case where...