Explore BrainMass



A force F of magnitude F making an angle theta with the x axis is applied to a particle located along axis of rotation A, at Cartesian coordinates (0, 0) The vector F lies in the xy plane, and the four axes of rotation A, B, C, and D all lie perpendicular to the xy plane. a). What is the torque (TA) about axis A due to the fo

Moment of Inertia

Ball a, of mass m_a, is connected to ball b, of mass m_b, by a massless rod of length L. The two vertical dashed lines in the figure, one through each ball, represent two different axes of rotation, axes a and b. These axes are parallel to each other and perpendicular to the rod. The moment of inertia of the two-mass system abou

magnetic flux and Faraday's law

1.) Suppose the largest surface of the body through which flux passes has an area of 0.024 m2 and a normal that is parallel to a magnetic field of 2.0 T. Determine the smallest time period during which the field can be allowed to vanish if the magnitude of the average induced emf is to be kept less than 0.010 V. For this one

Find the condition for the borderline case

A fountain has jets that squirt water in all directions at a speed of 16 ft/sec from a central point as shown. The dotted curve shows the boundary between the "dry" region (which the fountain doesn't reach) and the "wet" region reached by the water spray. Find the shape of this dotted curve, giving an equation for it (y as a f

Physics Problems.

6. If F1=50lb upward and F2=60lb upward ,the resultant and the direction of the resultant along the common line of action would be (A)10lb down (B)90lb up (C)110lb up (D)210lb up 7. A body that weighs 50lb is placed in contact with an inclined plane surface. The coefficient of friction between the surfaces is 0.25 and the angle

Rotational motion problems

At t=3s, a point on the rim of a .2m radius wheel has a tangential speed of 50m/s as the wheel slows down with a tangential acceleration of constant magnitude 10m/s^2. a) What is the constant angular acceleration? b) What is the angular velocities at t=3s & t=0s c) Through what angle did the wheel turn between t=0s & t=3s?

Strobe Light on a Fan

1. A strobe lights shines on a fan. By changing the speed of the strobe light, the fan appeared to run slower and sometimes even looked like it was stopping or running backwards. Assume the fan has three identical blades so that once the fan has rotated 1/3 around it looks exactly the same. Before turning on the strobe light we

A hoop of mass M and radius 1? rolls without slipping along a track which has the shape of a circle with radius 4R. It is subject to gravity. It is confined to a plane, so when the no-slip constraint is imposed there is just one degree of freedom. Find T, U, L, and the Lagrange equation. For small oscillations find the angular frequency of oscillation.

A hoop of mass M and radius 1? rolls without slipping along a track which has the shape of a circle with radius 4R. It is subject to gravity. It is confined to a plane, so when the no-slip constraint is imposed there is just one degree of freedom. Use the angle d as your coordinate. (This angle gives the location of the cente

Magnetic Field Intensity

1. A disc of Radius a lies on x-y plane with the z axis through its center. Surface Charge of uniform density P (row ) lies on the disk, which rotates about the Z axis at an angular velocity (ohm sign) rad/s. Find H (magnetic field intensity) at any point on the Z axis. Use BIOT-SAVART LAW. 2. A solid cylinder of radiu

Electricity & Magnetism Qualitative Problems

Here is a list of Qualitative problems which need the physics explained for each, diagrams, and equations with text are welcome. 1) The vector potential and the magnetic field inside and outside of a diamagnetic sphere in a uniform magnetic field 2) The vector potential and the magnetic field inside and outside of a unif

Basic Conceptual Physics

1. A ball is thrown up in the air. It goes up and then eventually comes down again. On its way up (after being let go), which is correct? A. Its acceleration decreases B. Its acceleration increases C. Its accelerations stays pretty much the same D. Impossible to stay unless the ball,s mass is known E. Impossible to sta

Angular acceleration of the disk

In problem 16.98(a), if the disk and drum have a total weight of 15 lb, and P has a magnitude of 4 lb, the angular acceleration of the disk is: a. 16.4 rad/s^2 b. 12.4 rad/s^2 c. 23.2 rad/s^2 d. 8.3 rad/s^2

Fractional excitation of a two-state ensemble

Temperature plays a role in determining the relevance of electronic, vibrational, and rotational spectral lines in room-temperature biomedical optics. The ratio between any two states' populations is an exponential function of ∆E, the difference in their energies, and kT, the Boltzmann energy, ratio is exp (-∆E=kT). Taki

Angular speed and rotational inertia of the cylinder

Show ALL your work, including the equations used to solve the problems. A uniform cylinder of radius 10 cm and mass 20 kg is mounted so as to rotate freely about a horizontal axis that is parallel to and 5.0 cm form the central longitudinal axis of the cylinder. a) What is the rotational inertia of the cylinder about the axis

Question about Electromagnetic Induction: Induced EMF

A) A 50-turn loop of wire has a cross-sectional area of 0.010 m^2. It is rotated about an axis perpendicular to the earth's field of 5.0 × 10^-5 T. What is the peak value of the emf generated if the loop rotates at 3600 rotations per minute? b) What would be the peak emf of the generating coil in the example above if it wer

Plane Mirror and Light Rays

I had some questions about mirrors, please provide supporting equations and information for these problems. - Does the mirror equation (p^-1 + d^-1 = 2R^-1 = f^1) apply to a plane mirror? What relationship between p and d does it imply? - Why is it when you stand in front of a mirror your left appears on your right and your

The Magnitude and Direction of Centripetal Acceleration

What is the magnitude and direction of the centripetal acceleration due to the earth's rotation at a location near Kansas City at 38 degrees latitude? I believe the answer is 2.66x10^-2 m/s^2, towards the earth's rotation axis. I need to see all formulas involved.

Multiple Choice Question son Velocity and Tension

A particle moves according to the equation x = 10t2, where x is in meters and t is in seconds. Find the average velocity for the time interval from 2.0 second to 3.0 second. 50 m/s 100 m/s 250 m/s 200 m/s A particle undergoes three consecutive displacements: d1 = (10i + 30j + 12k), d2 = (23

Moment of inertia - Parallel-Axis Theorem

To solve many problems about rotational motion, it is important to know the moment of inertia of each object involved. Calculating the moments of inertia of various objects, even highly symmetrical ones, may be a lengthy and tedious process. While it is important to be able to calculate moments of inertia from the definition, in

Moment of Inertia of two particles located in the x-y plane.

In this problem, you will answer several questions that will help you better understand the moment of inertia, its properties, and its applicability. --------- Diagram ------------------------ 1. On which of the following does the moment of inertia of an object depend? A. linear speed B. linear acceleration C.

11 Problems on Electromagnetism : A Complete Study

Please review the attached conceptual physics questions. Instead of just the answers, I would also like full explanations. This is so I can learn the material. Please make sure you are accurate and clear. Thanks. Please See attached word document

Rotating cylindrical axle

You are to design a rotating cylindrical axle to lift 800-N buckets of cement from the ground to a rooftop 78.0 m above the ground. The buckets will be attached to a hook on the free end of a cable that wraps around the rim of the axle; as the axle turns, the buckets will rise. 1. What should the diameter of the axle be in or

The Rotation Matrix

The rotation matrix [R], associated with a positive (in a right-hand sense) rotation α ; about the z-axis is: cosα sinα 0 -sinα cosα 0 0 0 1 ? Derive the rotation Matrix [Q] relating (x, y, z) to a system (x', y', z') which is described by three consecutive Euler rotations about z, then y

Four problems on speed distribution in gas molecules

(See attached file for full problem description with diagram and symbols) --- 1) Find the fractional number of molecules of a gas having speeds between vm and 1.05vm where vm = Sq.root(2kT/m) and is denoted as the most probable speed. [vm denotes v subscript m] 2) At what radial "distance" v from the origin of velocity

Spaceship rotation problem

A 20-meter-long spaceship is drifting in space, and is in the orientation shown below left, initially not spinning at all. The pilot needs to get the spaceship turned around 180 degrees, with the positions of the nose and tail switched around, as shown below right. To accomplish this, he fires a pair of small identical rocket

Rate of rotation of a collapsed star

A star rotates about its axis through a diameter once in 50 days. At the end of its life the star collapses to one hundredth of its orginal diameter. What will the rate of rotation of the collapsed star be?

Rotation: Tipping or sliding.

I have a 72" tall air-compressor that weights 120 pounds with a 20" base. I have a cart that is 36"wx72"l the surface of the cart where the compressor will be mounted is 10" off the ground. The cart wheels are in the corners, it is rated to carry 3600 pounds and weights 114 pounds. If the compressor is placed centered on the car

Magnetic effects of Current: Field, force, induction

1) The figure (*see attachment) shows 11 paths through a region of uniform magnetic field. One path is a straight line; the rest are half circles. The table (*see attachment) gives the masses, charges and speeds of the 11 particles that take these paths through the field in the direction shown. Which path corresponds to which pa

Moment of Inertia Tensor

Calculate the moment of inertia tensor for a solid hemisphere for rotation about its center of mass.