A solid cylindrical grinding wheel has a mass of m = 3.45 kg and a radius of 0.150 m. When the motor driving the wheel is switched on the wheel makes 745 revolutions as it accelerates from rest to an angular velocity of 225 rpm. Calculate the average torque on the wheel as it accelerates. A mb = 0.450 kg load is suspended from a light string that is wrapped around a mc = 2.50 kg pulley, which is a solid cylinder that has a radius of r = 3.50 cm. The cylinder is mounted on a frictionless horizontal axis, as shown in Figure 1, and the load falls freely. A motorcycle is put on its centre stand, so that the wheel can spin freely. As shown in Figure 2, the wheel can be approximated as an annular ring with an inner radius of R1 = 0.280 m and an outer radius of R2 = 0.330 m. The mass of the tire is m = 15.0 kg. (a) If the drive chain exerts a force of 2 400 N at a radius of 5.50 cm, what is the angular acceleration of the wheel? A ....... .n... (b) What is the tangential acceleration of a point on the outer edge of the tire? Thanos decides to slow Earth's rotation to once per 28.0 h by exerting an opposing force at and parallel to the equator. However you are not overly concerned, because you know that Thanos can only exert a force of F = 3_00 x 107 N (a little greater than the thrust of a Falcon 9 rocket). How long must Thanos push with this force to accomplish his goal? The mass of the Earth is m; = 5.97 x 1024 kg and the radius of the Earth is rE = 6.38 X 106 m. Enter your answer in billions of years