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24. A ceiling fan is initially motionless. When the fan is turned on, the fan blade undergoes an angular acceleration of 20 rad/s2. How long does it take to get the fan blade up to 6 = 60 rad/s? (a) 0.33 s (b) 1.0 s (c) 2.0 s (d) 3.0 s 25. A pendulum swings back and forth with a constant total energy. At the point in the swing when the pendulum reaches its maximum gravitational potential energy, what is its kinetic energy? (a) infinite (b) at a maximum, non-infinite value (c) at an intermediate value (d) zero a 26. You throw a rock sideways off of a bridge and it hits a distant rock below. While traveling, the only force on the rock is gravity. What is the exact shape of the path that the rock traveled along? (a) a straight line (b) a parabola (c) a sine function (d) a circular arc