# Torques

### Linear velocity of cylinders when rolling down an incline

A thin cylindrical shell and a solid cylinder have the same mass and radius. The two are released side by side and roll down, without slipping, from the top of an inclined plane that is 4.9 m above the ground. The acceleration of gravity is 9.8 m/s2 : Find the final linear velocity of the thin cylindrical shell. Answer in units

### Q#1 Explain (a) how it is possible for a large force to produce only a small or even zero, torque, and (b) how it is possible for a small force to produce a large torque. q#2 A hoop, a solid cylinder, a spherical shell, and a solid sphere are placed at rest at the top of an incline. All the objects have the same radius. They are then released at the same time. What is the order in which they reach the bottom? Justify your answer

Q#1 Explain (a) how it is possible for a large force to produce only a small or even zero, torque, and (b) how it is possible for a small force to produce a large torque. q#2 A hoop, a solid cylinder, a spherical shell, and a solid sphere are placed at rest at the top of an incline. All the objects have the same ra

### Physical Pendulum: Rotational simple harmonic motion.

Question: A straight uniform stick having a length b (m) and a mass M (kg) is freely pivoted at one end. Find the frequency of oscillation about the pivot, assuming the angle theta is small.

### If a spool initially at rest has a radius R and moment of inertia I, what is its angular speed after time T?

If a spool, initially at rest, has a radius R and a moment of inertia I, what is its angular speed after a time t?

### A uniform rod is supported by a rope against a wall. About what point of this system would you find the toque in order to find the force exerted by the rope? See attached file for full problem description.

A uniform rod is supported by a rope against a wall. About what point of this system would you find the toque in order to find the force exerted by the rope? See attached file for full problem description.

### Forces and Torques: Net torque applied to the cable car.

In San Francisco a very simple technique is used to turn around a cable car when it reaches the end of its route. The car rolls onto a turntable, which can rotate about a vertical axis through its center. Then, two people push perpendicularly on the car, one at each end, as in the drawing. The turntable is rotated one-half of a

### Forces and Torques

You are installing a new spark plug in your car, and the manual specifies that it be tightened to a torque that has a magnitude of 47 Nm. Using the data in the drawing, determine the magnitude F of the force that you must exert on the wrench.

### Rotational Energy on a solid disk

A uniform, solid disk with mass m and radius R is pivoted about a horizontal axis through its center. A small object of the same mass m is glued to the rim of the disk. If the disk is released from rest with the small object at the end of a horizontal radius, find the angular speed when the small object is directly below the

### Torque on a loop

A rectangular wire loop with a cross-sectional area of 5,000 cm^2 carries a current of 0.50 amperes. The loop is free to rotate about an axis that is perpendicular to uniform magnetic field strength of 0.40 Tesla. The plane of the loop is initially at an angle of 25 degrees to the direction of the magnetic field. What is the ma

### Torque on dipole

An electric dipole consists of charges +2e and -2e separated by 0.78 nm. It is in an electric field of strength 3.4 x 10^6 N/C. Calculate the magnitude of the torque on the dipole when the dipole moment is (a) parallel to (b) perpendicular to (c) antiparallel to the electric field. What is the difference between potential e

### Magnetic Field of Circular Coil

A small circular coil of 20 turns of wire lies in a uniform field of 0.5 T, so that the normal to the plane of the coil makes an angle of 60 degrees with the direction B (magnetic field with arrow over top). The radius of the coil is 4 cm, and it carries a current of 3 A. (a) what is the magnitude of the magnetic moment of the c

### Torque, Static, and Rotational Dynamics

1. Discuss the role of kinetic and potential energies in (a) golf, (b) tennis, and (c) basketball.

### Find the reaction force

For the beam and loading shown, determine the reaction force at end A and B. a. 40 kN b. 36 kN c. 12 kN d. 8 kN

### Angular acceleration of the rod

In problem 16.72(a), if the uniform slender rod weighs 15 lb, and the horizontal force P is 12 lb, the angular acceleration of the rod is: a. 44.2 rad/s^2 b. 82.8 rad/s^2 c. 55.2 rad/s^2 d. 35.2 rad/s^2

### Physics Experiment: Magnetic moment is found using a graph plotted between Torque and Magnetic field.

Physics Experiment: Balancing Magnetic Torque and Gravitational Torque. Magnetic moment is found using a graph plotted between Torque and Magnetic field.

### Castigliano's Method

Can someone show me how Castigliano's Method can be used to determine the elastic displacement of the red beam resulting from a torque placed on the circle (you can assume that the angular rotation of the circle is small ~ 2 or 3 degrees).

### Bowling Ball, Gyroscope & Flywheel

4. A bowling ball has a mass of 4.0 kg, a moment of inertia of 1.6x10 to the - 2nd kg.m2 and a radius of .20m. If it roll down a horizontal lane without slipping at a linear speed of 4.0 m/s, what is its total kinetic energy? 5. A gyroscope has a moment of inertia of .14 kg.m2 and has an initial angular velocity of 15 rad/s. Fr

### A student revolving on a piano stool with masses in both hands. To determine rotational kinetic energy of the system for different positions of his hands.

A student on a piano stool rotates freely with an angular speed of 3.16 rev/s. The student holds a 1.50 kg mass in each outstretched arm, 0.794 m from the axis of rotation. The combined moment of inertia of the student and the stool, ignoring the two masses, is 5.45 kg*m2, a value that remains constant. As the student pulls his

### A system comprising a rod with springs connected at each end. To calculate the deflection of springs using statis equilibrium and minimum potential energy concepts.

Deflection of springs. See attached file for full problem description.

### Rotational axes and maximum stresses

1. Two solid aluminum shafts (G = 3.7x106 psi) are connected by the gears shown. Ends B and D are fixed. What is the angle through which end C rotates? 2. For the beam of the cross section shown, determine the location of the neutral axis from the bottom of the beam. 3. For the beam of question 8, determine the value o

### Three problems on torque

1. At the local playground, a 16 kg child sits on the end of a horizontal teeter-totter, 1.5m from the pivot point. On the other side of the pivot an adult pushes straight down on the teeter-totter with a force of 95 N. In which direction does the teeter-totter rotate if the adult applies the force of a distance (a) 3.0 m, (b) 2

### Rotational Dynamics

A jet transport has a weight of 1.00x10^6 N and is at rest on the runway. The two rear wheels are 15m behind the front wheel, and the plane's center of gravity is 12.6m behind the front wheel. Determine the normal force exerted by the ground on the front wheel and each of the two rear wheels.

### Rotational Dynamics

Please help with the following problem. By means of a rope whose mass is negligible, two blocks are suspended over a pulley, as the drawing shows. The pulley can be treated as a uniform solid cylindrical disk. The downward acceleration of the 44.0-kg block is observed to be exactly one-half the acceleration due to gravity. N

### Theory of ballpoint pen.

Describe the energy changes that take place when a ballpoint pen is used. Decribe the forces that act in the use the ballpoint pen..

### Mass Moment of Inertia of the Pulley

At the instant shown in the figure, the stepped pulley rotates clockwise at 25 rad/sec, with a clockwise angular acceleration of 6 rad/sec^2. The masses of the two blocks are mA = 0Kg, ma = 5Kg, and the cables are inextensible. Find the mass moment of inertia of the pulley. (See attached file for full problem description)

### A window washer stands on a plank which is hung on two cables. Find the tension in the right cable.

See the diagram in the attached file. A window washer with a mass of 63.0 kg stands a distance, D = 0.800 m, from the left end of a plank of length, L= 1.90 m, with a mass of 17.0 kg. The plank is hung on two cables as shown. Find T2, the tension in the right cable.

### Two People Carrying a Mass Along an Inclined

Assume that W = 1.80 m, L = 3.30 m, angle = 21.0°, and that the weight of the mass is 39.90kg. What is the (vertical) weight carried by the builder at the rear? How do I set up the problem??

### Rotational Motion: Wheel is pulled on a curb.

(See attached file for full problem description with diagram and values) --- You are trying to raise a bicycle wheel of mass and radius up over a curb of height . To do this, you apply a horizontal force . 1. What is the least magnitude of the force that will succeed in raising the wheel onto the curb when the

### Zero Net Torque Conditions

Please see attachment for torque diagrams. Each of the four bars shown can rotate freely in the horizontal plane about its left end. For which diagrams is the net torque equal to zero?