A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 187-mile trip in a typical midsize car produces about 2.84 x 109 J of energy. How fast would a 9.42-kg flywheel with a radius of 0.237 m have to rotate to store this much energy? Give your answer in rev/min.

To drive a typical car at 40 mph on a level road for one hour requires about 3.2 × 10^7 J of energy. Suppose we tried to store this much energy in a spinning, solid, uniform, cylindrical flywheel. A large flywheel cannot be spun too fast or it will fracture. If we used a flywheel of diameter 1.26 m and mass 450 kg, what angular speed would be required to store 3.2 x 10^7 J? Give your answer in rad/s.

Your grandmother enjoys creating pottery as a hobby. She uses a potter's wheel, which is a stone disk of radius R = 0.430 m and mass M = 100 kg. In operation, the wheel rotates at 45.0 rev/min. While the wheel is spinning, your grandmother works clay at the center of the wheel with her hands into a pot-shaped object with circular symmetry. When the correct shape is reached, she wants to stop the wheel in as short a time interval as possible, so that the shape of the pot is not further distorted by the rotation. She pushes continuously with a wet rag as hard as she can radially inward on the edge of the wheel and the wheel stops in 6.00 s. (a) You would like to build a brake to stop the wheel in a shorter time interval, but you must determine the coefficient of friction between the rag and the wheel in order to design a better system. You determine that the maximum pressing force your grandmother can sustain for 6.00 s is 60.0 N. HK (b) What If? If your grandmother instead chooses to…

A uniform rod is set up so that it can rotate about an axis at perpendicular to one of its ends. The length and mass of the rod are 0.759 m and 1.31 kg, respectively. A force of constant magnitude F acts on the rod at the end opposite the rotation axis. The direction of the force is perpendicular to both the rod's length and the rotation axis. Calculate the value of F that will accelerate the rod from rest to an angular speed of 6.69 rad/s in 8.49 s. F =

A 650 kg dragster accelerates from rest to a final speed of 110 m/s in 400 m (about a quarter of a mile) and encounters an average frictional force of 1200 N. What is its average power output in watts and horsepower if this takes 7.30 s? W=?

Delivery trucks that operate by making use of energy stored in a rotating flywheel have been used in Europe. The trucks are charged by using an electric motor to get the flywheel up to its top speed of 1,000.0rad/s. One such flywheel is a solid disc, rotating about its central axis, with a mass of 1,010.0kg and a radius of 1.2m. What is the kinetic energy (in J) of the flywheel after charging?

A horizontal platform in the shape of a circular disk rotates on a frictionless bearing about a vertical axle through the center of the disk. The platform has a radius of 1.83 m and a rotational inertia of 261 kg⋅m² about the axis of rotation. A 73.1 kg student walks slowly from the rim of the platform toward the center. If the angular speed of the system is 1.97 rad/s when the student starts at the rim, what is the angular speed when she is 0.673 m from the center? Number Units

Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel's energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 2.0 m diameter and a mass of 260 kg. Its maximum angular velocity is 1400 rpm. A motor spins up the flywheel with a constant torque of 58 Nm. How long does it take the flywheel to reach top speed? How much energy is stored in the flywheel?

A propeller is modeled as five identical uniform rods extending radially from its axis. The length and mass of each rod are 0.875 m and 2.71 kg, respectively. When the propellor rotates at 519 rpm (revolutions per minute), what is its rotational kinetic energy ??

A bowling ball with a mass of 7.0 kg, a radius of 11 cm and a rotational inertia of 0.034 kg/m2 rolls down a lane at a velocity of 4.3 m/s.  Determine the total kinetic energy of the bowling ball.  Hint: If a ball is rolling without slipping then ω=v/r.  The total kinetic energy is the rotational kinetic energy plus the translational kinetic energy.