Answered: 5. A grinder disc of mass 2.0 kg with…

5. A grinder disc of mass 2.0 kg with 8.0 cm radius rotates at 500 rev/min. What is its rotational kinetic energy? c) 26 J a) 8.8 J b) 17 J d) 43 J

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter10: Rotational Motion And Angular Momentum

Section: Chapter Questions

Problem 12CQ: The Earth has more rotational kinetic energy now than did the cloud of gas and dust from which it...

See similar textbooks

Similar questions

A basketball player entertains the crowd by spinning a basketball on his nose. The basketball has a mass of 0.600 kg and a radius of 0.121 m. If the basketball is spinning at a rate of 3.00 revolutions per second, (a) what is its rotational kinetic energy? (See Section 8.6.) (b) What is the magnitude of its angular momentum? Treat the ball as a thin, spherical shell. (See Section 8.7.)
A cylinder of mass 10.0 kg rolls without slipping on a horizontal surface. At a certain instant, its center of mass has a speed of 10.0 m/s. Determine (a) the translational kinetic energy of its center of mass, (b) the rotational kinetic energy about its center of mass, and (c) its total energy.
An automobile engine can produce 200 N m of torque. Calculate the angular acceleration produced if 95.0% of this torque is applied to the drive shaft, axle, and rear wheels of a car, given the following information. The car is suspended so that the wheels can turn freely. Each wheel acts like a 15.0 kg disk that has a 0.180 m radius. The walls of each tire act like a 2.00-kg annular ring that has inside radius of 0.180 m and outside radius of 0.320 m. The tread of each tire acts like a 10.0-kg hoop of radius 0.330 m. The 14.0-kg axle acts like a rod that has a 2.00-cm radius. The 30.0-kg drive shaft acts like a rod that has a 3.20-cm radius.
The Earth has more rotational kinetic energy now than did the cloud of gas and dust from which it formed. Where did this energy come from? Figure 10.33 An immense cloud of rotating gas and dust contracted under the influence of gravity to form the Earth and in the process rotational kinetic energy Increased. (credit: NASA)
A grindstone increases in angular speed uniformly from 4.00 rad/s to 12.0 rad/s in 4.00 s. (a) Calculate the grindstones angular acceleration. (b) Through what angle does it turn during that time? (See Section 7.2.)
Four objectsa hoop, a solid cylinder, a solid sphere, and a thin, spherical shelleach have a mass of 4.80 kg and a radius of 0.230 m. (a) Find the moment of inertia for each object as it rotates about the axes shown in Table 8.1. (b) Suppose each object is rolled down a ramp. Rank the translational speed of each object from highest to lowest, (c) Rank the objects rotational kinetic energies from highest to lowest as the objects roll down the ramp.
A bar on a hinge starts from rest and rotates with an angular acceleration = 10 + 6t, where is in rad/s2 and t is in seconds. Determine the angle in radians through which the bar turns in the first 4.00 s.
A car is designed to get its energy from a rotating solid-disk flywheel with a radius of 2.00 m and a mass of 5.00 102 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheels rotational speed up to 5.00 103 rev/min. (a) Find the kinetic energy stored in the flywheel, (b) If the fly-wheel is to supply energy to the car as a 10.0-hp motor would, find the length of time the car could run before the flywheel would have to be brought back up to speed.
Conservation of Angular Momentum 52.A disk of mass 2.0 kg and radius 60 cm with a small mass of 0.05 kg attached at the edge is rotating at 2.0 rev/s. The small mass suddenly separates from the disk. What is the disk’s final rotation rate?
Calculate the rotational kinetic energy in the motorcycle wheel (Figure 10.38) if its angular velocity is 120 rad/s. Assume M=12.0kg,R1=0.280m, and R2=0.330m .
In softball, the pitcher throws with the arm fully extended (straight at the elbow). In a fast pitch the ball leaves the hand with a speed of 139 km/h. (a) Find the rotational kinetic energy of the pitcher's arm given its moment of inertia is 0.720kg-m2 and the ball leaves the hand at a distance of 0.600 m from the pivot at the shoulder. (b) What force did the muscles exert to cause the arm to rotate if their effective perpendicular lever arm is 4.00 cm and the ball is 0.156 kg?
Angular Speed and Angular Acceleration (a) Find the angular speed of Earths rotation about its axis. (b) How does this rotation affect the shape of Earth?