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figure 1 shows the angular velocity versus time graph for a particle moving in a

ID: 1777847 • Letter: F

Question

figure 1 shows the angular velocity versus time graph for a particle moving in a circle how many revolutions does the object make during the first 3.3 MasteringPhysics CH 04 HW Problem 4.23- Enhanced - with Feedback previous | 11 of 15 Problem 4.23-Enhanced-with Feedback Part A (Figure 1) shows the angular-velocity-versus-time graph for a particle moving in a circle. How many revolutions does the object make during the first 3.3 s ? You may want to review (pages 93-96) Submit My Answers Give Up Figure 1 of 1 Incorrect; Try Again; 4 attempts remaining Continue (rad/s) 20t 10- t (s) 0

Explanation / Answer


from t = 0 to t = 2 s the slope is zero angular velocity is constant

angle rotated theta1 = w*t = 20*2 = 40 rad

from t = 2 to   t = 3 s the angular speed changes


angular acceleration alpha = (10-20)/(3-2) = -10 rad/s^2

from t = 2s to t = 3 s

anlge rotated theta2 = 20*(3-2) - (1/2)*10*(3-2)^2 = 15 rad


from t =3 s the angular speed is constantand is equal to 10 rad/s

from t = 3s to t = 3.3 s

angle rotated theta3 = 10*(3.3-3) = 3 rad

total angle rotated = theta1 + theta2 + therta3 = 40 + 15 + 3 = 58 rad

number of revolutions n = 58/(2pi) = 9.23 revolution per second