Exam 11: Rolling, Torque, and Angular Momentum

A particle is located on the x axis at x = 2.0 m from the origin.A force of 25 N, directed 30° above the x axis in the x-y plane, acts on the particle.What is the torque about the origin on the particle?

Which of the following is a vector quantity?

When we apply the energy conversation principle to a cylinder rolling down an incline without sliding, we exclude the work done by friction because:

A particle moves along the x axis.In order to calculate the angular momentum of the particle, you need to know:

A forward force acting on the axle accelerates a rolling wheel on a horizontal surface.If the wheel does not slide the frictional force of the surface on the wheel is:

A cylinder of radius R = 6.0 cm is on a rough horizontal surface.The coefficient of kinetic friction between the cylinder and the surface is 0.30 and the rotational inertia for rotation about the axis is given by MR²/2, where M is its mass.Initially it is not rotating but its center of mass has a speed of 7.0 m/s.After 2.0 s the speed of its center of mass and its angular velocity about its center of mass, respectively, are:

A particle moves along the x axis.In order to calculate the torque on the particle, you need to know:

A hoop (I = MR²)of mass 2.0 kg and radius 0.50 m is rolling at a center-of-mass speed of 15 m/s.An external force does 750 J of work on the hoop.What is the new speed of the center of mass of the hoop?

What is precession?

A 2.0-kg block starts from rest on the positive x axis 3.0 m from the origin and thereafter has an acceleration given by in m/s².The torque, relative to the origin, acting on it at the end of 2.0 s is:

A solid wheel with mass M, radius R, and rotational inertia MR²/2, rolls without sliding on a horizontal surface.A horizontal force F is applied to the axle and the center of mass has an acceleration a.The magnitudes of the applied force F and the frictional force f of the surface, respectively, are:

A hoop, a uniform disk, and a uniform sphere, all with the same mass and outer radius, start with the same speed and roll without sliding up identical inclines.Rank the objects according to how high they go, least to greatest.

When a woman on a frictionless rotating turntable extends her arms out horizontally, her angular momentum:

A single force acts on a particle P.Rank each of the orientations of the force shown below according to the magnitude of the time rate of change of the particle's angular momentum about the point O, least to greatest.

A man, holding a weight in each hand, stands at the center of a horizontal frictionless rotating turntable.The effect of the weights is to double the rotational inertia of the system.As he is rotating, the man opens his hands and drops the two weights.They fall outside the turntable.Then:

A 2.0-kg stone is tied to a 0.50-m long string and swung around a circle at a constant angular velocity of 12 rad/s.The net torque on the stone about the center of the circle is:

A 5.0-kg ball rolls without sliding from rest down an inclined plane.A 4.0-kg block, mounted on roller bearings totaling 100 g, rolls from rest down the same plane.At the bottom, the block has:

A phonograph record is dropped onto a freely spinning turntable.Then:

Two objects are moving in the x, y plane as shown.If a net torque of 44 N∙m acts on them for 5.0 seconds, what is the change in their angular momentum?

A uniform disk has radius R and mass M.When it is spinning with angular velocity $\omega$ about an axis through its center and perpendicular to its face its angular momentum is I $\omega$ .When it is spinning with the same angle velocity about a parallel axis a distance h away its angular momentum is: