Two uniform solid spheres have the same mass of 2.85 kg, but one has a radius of 0.236 m while the other has a radius of 0.894 m. Each can rotate about an axis through its center. (a) What is the magnitude t of the torque required to bring the smaller sphere from rest to an angular speed of 317 rad/s in 15.5 s? N.m (b) What is the magnitude F of the force that must be applied tangentially at the sphere's equator to provide that torque? (c) What is the corresponding value of t for the larger sphere? N. m

A student holds a bike wheel and starts it spinning with an initial angular speed of 9.0rotations per second. The wheel is subject to some friction, so it gradually slows down. In the 10 s period following the inital spin, the bike wheel undergoes 70 complete rotations. Assuming the frictional torque remains constant, how much more time Δts will it take the bike wheel to come to a complete stop? The bike wheel has a mass of 0.625 kg and a radius of 0.315 m. If all the mass of the wheel is assumed to be located on the rim, find the magnitude of the frictional torque τf that was acting on the spinning wheel.

An electric motor rotating a workshop grinding wheel at 1.08 x 10 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.06 rad/s? (a) How long does it take the grinding wheel to stop? Note that the time required for the wheel to stop is the same as the time for the wheel to start from rest and reach the given angular speed with the same magnitude angular acceleration, s (b) Through how many radians has the wheel turned during the time interval found in part (a)? It might be helpful to translate this problems into linear variables (a car traveling with an initial speed and then slowing down with a constant negative acceleration), rad Need Help? Road Master

Problem 2: A wheel with radius r= 1.8 m has a tangential force F = 14.2 N acting on it as shown. F Part (a) What is the magnitude of the torque about the center of the wheel, in N•m? N•m sin() cos() tan() 7 8 9 НОMЕ cotan() asin() acos() E ↑^^| 4 5 6. atan() acotan() sinh() 1 3 cosh() tanh() cotanh() END O Degrees Radians VO BACKSPАСЕ DEL CLEAR Part (b) What is the direction of the torque?

A dragster starts from rest and accelerates down a track. Each tire has a radius of 0.320 m and rolls without slipping. At a distance of 393 m, the angular speed of the wheels is 253 rad/s. Determine (a) the linear speed of the dragster and (b) the magnitude of the angular acceleration of its wheels.

A 150 g baseball is pitched at 32.8 m/s and spinning at 42 rad/s. You can treat the baseball as a uniform solid sphere of radius 3.7 cm. What fraction (in %) of its kinetic energy is rotational?

A playground merry-go-round, made in the shape of a solid disk, has a diameter of 2.50 m and a mass of 350.0 kg. Two children, each of mass 30.0 kg, sit on opposite sides at the edge of the platform. Approximate the children as point masses. What torque is required to bring the merry-go-round from rest to 28.0 rev/min in 23.0 s?