Physics Rotational Mechanics Level: High School
Equilibrium
A roller in 20 inches in diameter and weighs 100 lbs, What horizontal force is necessary to pull it over a brick 2 inches high ?And find the force of the brick in the roller (both magnitude and direction)
Physics Rotational Mechanics Level: High School
A meter stick pivoted about a horizontal axis through the 0-cm end is held in a horizontal position and let go . Which position on the meter stick has a tangential acceleration equal to the acceleration due to gravity ?
Physics Rotational Mechanics Level: High School
Suppose the inclined plane above were frictionless and the sphere slid down the plane instead of rolling . What would the new linear speed before the sphere’s center of mass .
Physics Rotational Mechanics Level: High School
A thin walled uniform sphere is released from the top of an inclined plane 0.25m tall . The sphere rolls down the plane with out slipping and there is no energy loss from friction . What is the linear speed for the sphere’s center of mass at the bottom of the incline .
Physics Rotational Mechanics Level: High School
By means of a rope whose mass is negligible , two blocks are suspended over a pulley as the drawing shows at “click here” , with m1 = 12.2 kg and m2 = 42.7 kg . The pulley can be treated as a uniform , solid , cylindrical disk . The downward acceleration of the 42.7 kg block is observed to be exactly one-half the acceleration due to gravity . Noting that the tension in the rope is not the same on each side of the pulley , find the mass of the pulley .
Physics Rotational Mechanics Level: High School
A bowling ball encounters a 0.76 m vertical rise on the way back to the ball rack , as the drawing at “click here” illustrates . Ignore frictional losses and assume that the mass of the ball is distributed uniformly . If the translational speed of the ball is 5.00 m/s at the top .
Physics Rotational Mechanics Level: High School
Equilibrium
A uniform plank of length 4.2 m and weight 220 N rests horizontally on two supports , with 1.1 m of the plank hanging over the right support (see the drawing at “click here” ) To what distance x can a person who weighs 445 N walks on the overhanging part of the plank before it just begins to tip ?
Physics Rotational Mechanics Level: High School
A playground carousel is free to rotate about its center on frictionless bearings , and air resistance is negligible . The carousel itself (without riders) has a moment of inertia of 125 kg*m^2 . When one person is standing at a distance of 1.50 m from the center , the carousel has an angular velocity of 0 590 rad/s . However , as this person moves inward to a point located 0.750 m from the center , the angular velocity increases to 0.690 rad/s . What is the person’s mass ?
Physics Rotational Mechanics Level: High School
A solid disk rotates at an angular velocity of 0.028 rad/s with respect to an axis perpendicular to the disk at its center . The moment of inertia of disk is 0.17 kg*m^2 . From above , sand is dropped straight down onto this rotating disk , so that a thin uniform ring of sand is formed at a distance of 0.40 m from the axis . The sand in the ring has a mass of 0.50 kg . After all the sand is in place , what is the angular velocity of the disk ?
Physics Rotational Mechanics Level: High School
A flat uniform circular disk (radius = 2.50 m , mass = 1.00 x 10^2 kg ) is initially stationary . The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the centre of the disk . A 40.0 kg person , standing 1.70 m from the axis , begins to run on the disk in a circular path and has a tangential speed of 2.30 m/s relative to the ground .(a) Find the resulting angular speed of the disk (in rad/s)
(b) Describe the direction of the rotation .
Physics Rotational Mechanics Level: High School
A helicopter has two blades as shown in the figure at ”click here“ each of which has a mass of 240 kg and can be approximated as a thin rod of length R = 7.7m . The blades are rotating at an angular speed of 47 rad/s .(a) What is the total moment of inertia of the two blades about the axis of rotation ?
(b) Determine the rotational kinetic energy of the spinning blades.
Physics Rotational Mechanics Level: High School
Assume that the earth is a uniform sphere and tht its path around the sun is circular .(a) Calculate the kinetic energy that the earth has because of its rotation about its own axis . For comparison , the total energy used in the United States in one year is about 9.33 x 10^9 J .
(b) Calculate the kinetic energy that the earth has because of its motion around the sun .
Physics Rotational Mechanics Level: High School
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 370 mile tip in a typical midsize car produces about 1.30 x 10^9 J of energy . How fast would a 17 kg flywheel with a radius of 0.27m have to rotate in order to store this much energy ? Give your answer in rev/min .
Physics Rotational Mechanics Level: High School
A solid cylindrical disk has a radius of 0.20m . It is mounted to an axle that is perpendicular to the circular -end of the disk at its center . When a 35 N force is applied tangentially to the disk , perpendicular to the radius , the disk acquires an angular acceleration of 130 rad/s^2 . What is the mass of the disk ?
Physics Rotational Mechanics Level: High School
A rotating door is made from four rectangular glass panes. As shown in the drawing . The mass of each pane is 87 kg . A person pushes on the outer edge of the one pane with a force of F = 56 N that is directed perpendicular to the pane . Determine the magnitude of the doors angular acceleration .