Explore BrainMass


Magnitude of the force F applied tangentially

See attached figure.jpg The mechanism shown in the figure is used to raise a crate of supplies from a ship's hold. The crate has total mass 56 kg. A rope is wrapped around a wooden cylinder that turns on a metal axle. The cylinder has radius 0.20 m and a moment of inertia = 3.0 kg*m^2 about the axle. The crate is suspended

Tensions in Each Cable; Speed of Wagon After Moving Up the Hill

1. Two window washers, Bob and Doris, are on a uniform 3.00 m long, 345 N scaffold supported by two cables attached to its ends. Doris, who weighs 750 N stands 1.00 m from the end. Two meters from the left end is the 500 N washing equipment. Bob is 0.500 m from the right end and weighs 1000 N. Given that the scaffold is in rota

Determine the Maximum Torque on the Shaft

See the attached file. The arrangement in attached figure shows a simple prototype motor with an armature shaft carrying two identical loops each with effective area of 20 cm^2 and placed at right angles to each other. The loops are connected in parallel to a commutator. Determine the maximum torque on the shaft if the mot

Least amount of current through a coil

A wood cylinder of mass m = .250 kg and length L=.100m, with N =10.0 turns of wire wrapped around it longitudinally, so that the plane of the wire coil contains the long central axis of the cylinder. The cylinder is released on a plane inclined at an angle theta to the horizontal, with the plane coil parallel to the incline plan

Tensions of the pulley ropes

Two blocks are attached to a rope and wrapped around a pulley as shown in the attachment. The pulley is a DISK of mass 20.0 kg and radius 3.00 meters. The pulley and surface are frictionless and the system is released from the rest. Find the tensions of the rope on either sides of the pulley. Please refer to the attachmen

Length of Time for a Cylinder to Stop Rotating: Example Question

A solid cylinder of mass 4.1 kg and radius 23 cm rotates with angular speed of 5.0 rev/s. Another object is brought in contact with the cylinder while rotating causing a tangential force of friction equal to 2.5 N. How long will it take for the cylinder to stop?

Physics: Meter stick period of oscillation; piston maximum speed

41 A uniform meter stick swings about a pivot point which is a distance x = 27.4 cm from the end of the stick. What is its period of oscillation? 83 The piston in the cylinder head of a locomotive has a stroke (twice the amplitude) of 0.66 m. If the piston moves with simple harmonic motion with an angular frequency of 180

Principle Stresses for Elements

The figure shows a schematic of typical steel (E=200GPa, v=0.3) kneed support. The shaft has a diameter of 16mm. The dimensions are a=150mm and b=300mm and the forces are F=100N, P=75N and P2=50N. At the wall, Kt=1.75 and Kts=2. Considering the Generalized Hooke's law: a. What are the principal stresses at the critical stress

General Questions: Six Questions to Learn Concepts

1. The Moon is centripetally accelerating towards the Earth. Explain why it is not getting closer to the Earth. 2. Why is it easier to hold a 10lb weight next to your body instead of with your arm outstretched? 3. When you design a building in an earthquake region, how should the natural frequencies of oscillation of the b

Simple Harmonic Motion: Simple Pendulum.

A simple pendulum is made from a 0.883 m long string and a small ball attached to it's free end. The ball is pulled to the side through a small angle and then released from rest. After the ball is released how much time elapses before it attains it's greatest speed?

Electric Motor at Different Voltages

If a motor requires 6 Watts to run it, does it make a difference how that power is obtained? For example: Will 0.5 volts times 12 Amps run the motor the same as 12 Volts times 0.5 Amps wii? Each gives 6 Watts but the way they are generated is different.

Cylinder of mass and radius is rolling on a stationary larger

A cylinder of mass m and radius a is rolling on a stationary larger cylinder of radius R. At what angle will the smaller cylinder will leave the surface and what is the friction force between the cylinders (assume coefficient mu). Please see the attached file for full problem description.

Force Exerted By each Student on the Couch

Two students carry a couch up a flight of stairs at a constant speed. The couch is 2.20 m long, makes an angle of 35.0° with the horizontal, and weighs 190 N. The upper student exerts a horizontal force on the top end of the couch; the lower student holds the bottom end of the couch. Find the magnitude of the force exerted by e

Mechanics: Force and Its Moment (Torque)

The figure shows a lower leg being exercised (see the attached file). It has a 49-N weight attached to the foot and is extended at an angle with respect to the vertical. Consider a rotational axis at the knee, as indicated. (a) When = 54°, find the magnitude of the torque that the weight creates. (b) At what angle does the m

A Block of Mass Being Released From a Pulley

A block of mass M2 = 4kg hangs from a rope that is wrapped around a frictionless pulley and connected to another mass M1 = 2kg that is at rest on a frictionless table. The mass of the pulley is 2kg and its radius is 0.1m. When the blocks are released: a) What is the acceleration of the masses? b) What is the tension, T1, in

Angular motion of the baggage carousel

A baggage carousel at an airport is rotating with an angular speed of 0.18 rad/s when the baggage begins to be loaded onto it. The moment of inertia of the carousel is 1000.0 kgm2. Ten pieces of baggage with an average mass of 25.0 kg each are dropped vertically onto the carousel and come to rest at a perpendicular distance of 2

Magnetic fields: Torque on a current carrying square wire

A single square loop of wire 21.0 cm on a side is placed with its face parallel to the magnetic field between the pole pieces of a large magnet. When 6.21 A flows in the coil, the torque on it is 0.315 m·N. What is the magnetic field strength?

List and define each of Newton's Laws governing linear motion

3. List (by number and name) and define with words or equations each of Newton's Laws governing linear motion. Give a real life example illustrating each. 4. A person performs a standard long jump from the ground (takeoff and landing surfaces the same). Using a total flight time of 0.43 s and a horizontal displacement

Rotational Simple Harmonic Oscillation: Rod with two springs

A 1-dimensional rod 2 meters long of mass 60 grams uniformly distributed has an axle through its midpoint allowing the rod to rotate in a vertical plane. At each end of the rod are identical, ideal springs which have spring constants of 40 N/cm. At equilibrium the rod lies horizontally in the vertical plane. The rod is given

Magnetic moment

A plana loop of area A=0.05m^2 carries a current I=1A. The magnetic field B=0.5T is at angle 45 degrees with the norm to the loop. 1.)What is magnetic moment of the loop. 2.)What torque should be applied to the loop in order to keep it at rest. 3.)What torque would be needed if the loop had 100 turns

Forces and torque on an electric dipole

For two equal in magnitude but opposite charges +Q and -Q we can define a vector of dipole moment p, with the magnitude absolute value (p)=dxQ, where d is the distance between the charges. The direction of p is the direction from negative to positve charge (see figure) 1.)What force acts on the dipole in a uniform electric f

Three problems on forces.

A. A claw hammer is used to pull a nail out of a board. The nail is at a 60 degree angle of to the board, and a force F1 of magnitude 500N applied to the nail is required to pull it from the board. The hammer head contacts the board at point A, which is 0.080m from where the nail enters the board. A horizontal force F2 is appl

Friction on inclined plane

5. A rectangular block twice as high as it is wide is resting on a board. The coefficient of static friction between board and incline is .63. If the board is tilted will the block first tip over or begin sliding? 6. A uniform pole of mass M is at rest on an incline of angle secured by a horizontal rope. For what angle

Rotational Dynamics:Motion of wheels of an stopping airplane

An airliner lands with a speed of 100 m/s. Each wheel of the plane has a radius of 1.5 m and a moment of inertia of 120 kg?m2. At touchdown the wheels begin to spin under the action of friction. Each wheel supports a weight of 1.50 x 10^4 N, and the wheels attain the angular speed of rolling without slipping in 0.5 s. What is th

Lagrange Equations: Kinetic Energy of a Particle

There is a case in which a bead is constrained to move on a wire shaped like a parabola. Now consider the case of a point-like bead constrained to move on the surface of a parabolic cup, whose equation, in cylindrical coordinates, is given by z = br2. Write down the kinetic energy of the particle and the generalized forces. Use

forces on the ground and on the wall by the ladder

Please see the attached file. 3. a 12 ft ladder that weighs 50 lb rests against a frictionless wall at a point 10 ft above the ground. How much force does the ladder exert (a) on the ground and (b) on the wall?


Please see the attached file. A horizontal boom 8 ft long is attached to a wall at its inner end and is supported at its outer end by a cable that makes an angle 30° with the boom. The boom weighs 60 lb, and a load of 500 lb is attached to its outer end. Find the (a) tension T in the cable and (b) the compression force F in