Share
Explore BrainMass

Energy

Compressive force on rod

The ball has a weight of 15 lb and is fixed to a rod having a negligible mass. If it is released from rest when theta = 0 deg., determine the angle theta at which the compressive force in the rod becomes zero (see attachment for an illustration) answer should be 48.2 deg. Not sure how to get there though.

Potential energy

The Great Sandini is a circus performer with mass 60.0 kg who is shot from a cannon (actually a spring gun). You don't find many men of his caliber, so you help him design a new gun. This new gun has a very large spring with a very small mass and a force constant of 1300 N/m that he will compress with a force of 5000 N. The insi

Hockey Collision

Ice-hockey star Wayne Gretzky is skating at 13.0 m/s toward a defender, who in turn is skating at 5.0 m/s toward Gretzky. Gretzky's weight is 756 N; that of the defender is 900 N. Immediately after the collision, Gretzky is moving at 1.5 m/s in his original direction. You can ignore external horizontal forces applied by the ice

Applying the Conservation Laws

A 2.5 kg block collides with a horizontal spring of negligible mass and spring constant. k=320 N/m. The block compress the spring by 8.5 cm from its rest position. How fast was the block going when it hit the spring if the frictional coefficient between the block and the horizontal surface is 0.40?

Conservation of Momentum in Two and Three Dimension Collision

Two pendulums are hung adjacent to each other. Bob 1 has a mass m, and bob 2 has a mass 2m. Bob 1 is pulled aside until the support string makes an angle of 45 degrees with the vertical direction and then released. When the bobs bollide, the stick together. What is the maximum angle made by the support strings with respect to th

Conservation of energy

PLEASE SHOW ALL WORK WITH CORRECT ANSWER!!! 8. 40 A rocket is projected upward from the earth's surface (r=Re) WITH AN INITIAL SPEED Vo that carries it to a distance r=1.5Re from the center of the earth. What is the launch speed Vo? Assume that air friction can be ignored and give your answer in terms of g and Re. Hint in

Elastic Collision in One Dimension

Two air-track gliders of equal mass are initially moving in the same direction alone a straight line. The rearmost glider has an initial speed of 3.0 m/s and the forward glider has a speed of 2.0 m/s. if the collision is elastic, what are the speeds and directions of the gliders after the collision?

Light Problem Set

1. (a) What are the wavelength and color of the line in the Balmer spectrum for n2=4? (b) What are the wavelength and color of the line for n2=5? a. a) 486.08 nm and blue b) 434.00 nm and violet b. a) 686.08 nm and red b) 634.00 nm and red c. a) 386.08 nm and ultra violet b) 334.00 nm and ultra violet d. a) 5

Multiple Choice Questions-Light

1. A myopic person wears eyeglasses with a lens strength of - 3.5 diopters. Where is the far point for that person's eyes? a. 3.5 m b. 25 cm c. 28.6 cm d. infinity 2. Red light of wavelength 632.8 nm is incident on a pair of slits whose separation is 0.75mm. What is the separation of neighboring interfer

rate of change of mechanical energy for a damped

Show that the time rate of change of mechanical energy for a damped, undriven oscillator is given by dE/dt = -bv^2 and hence is always negative. Proceed as follows: Differentiate the expression for the mechanical energy of as oscillator, E = 1/2mv^2 + 1/2kx^2 and use the following equation: -kx -b dx/dt = m d^2x/dx^2

Calculating elastic potential energy

A 3.2 kg block is hanging stationary from the end of a vertical spring that is attached to the ceiling. The elastic potential energy of this spring/mass system is 1.6 J. What is the elastic potential energy of the system when the 3.2 kg block is replaced by a 5.6 kg block?

Calculating speed as a function of distance

The scheme presents two blocks: The first, Block A, is on a table. Block A is attached to an end of a string. At the end of the table, there is a pulley; the string passes by this pulley, then becomes vertical. At the other end of this string (end of this vertical string) there is Block B. So Block A is attached to Block B by

Coefficient of Kinetic Friction.

Please do not put your response in a .pdf format, but Word documents are okay. Thanks! A sled is being held at rest on a slope that makes an angle theta with the horizontal. After the sled is released, it slides a distance d_1 down the slope and then covers the distance d_2 along the horizontal terrain before stopping. Find t

A partially inelastic collision

3.) A car of mass 1148 kg has kinetic energy of 117 kJ. The driver sees a stalled SUV of mass 2700 kg blocking the intersection. Because he is having a bad hair day, the driver plows into the SUV without braking. The two vehicles stick together (a perfectly inelastic collision) and slide to a stop. a) How much work is done a

Bungee jumping, Energy

Kate, a bungee jumper, wants to jump off the edge of a bridge that spans a river below. Kate has a mass m, and the surface of the bridge is a height h above the water. The bungee cord will first straighten and then stretch as Kate falls. Assume that the bungee cord behaves as an ideal spring once it begins to stretch. Neglect

Physics - Collision (Elastic versus Inelastic)

A package of mass m is released from rest at a warehouse loading dock and slides down a 3.0-m high frictionless chute to a waiting truck. Unfortunately, the truck driver went on a break without having removed the previous package, of mass 2m, from the bottom of the chute. A. Suppose the packages stick together. What is their

Gravitational Potential Energy of a Lake

A hydroelectric dam holds back a lake of surface area 3.0*10^6 m^2 that has vertical sides below the water level. The water level in the lake is 150 m above the base of the dam.When the water passes through turbines at the base of the dam, its mechanical energyis converted into electrical energy with 90per cent efficiency. 1)

Spring Energy Question

A block of mass M on a horizontal frictionless table is connected to a spring (constant k). The block is at the left and attached to an horizontal spring , and the right end of the spring is itself attached to the wall. The block is set in motion so that it oscillates about its equilibrium point with a certain amplitude Ao. The

Mechanical Energy

A block of mass M slides along a horizontal table with speed Vo. At x=0 it hits a spring with spring constant k and begins to experience a friction force. The coefficient of friction is variable and is given by Mu=b*x, where b is a constant. Find the loss in mechanical energy when the block has first come momentarily to re

Mechanical Energy Laws

Mass m whirls on a frictionless table, held to circular motion by a string which passes through a hole in the table. The string is slowly pulled through the hole so that the radius of the circle changes from L1 to L2. Show that the work done in pulling the string equals the increase in kinetic energy of the mass.

Energy Stored in a Magnetic Field

An air-core solenoid with 63 turns is 8.00 cm long and has a diameter of 1.20 cm. How much energy is stored in its magnetic field when it carries a current of 0.780 A? (answer in µJ)

Electric potential energy

Does the electric field always move from positive to negative? If I'm told that a uniform electric field of magnitude 4.1 x 10^5 N/C points in the positive x direction, and a 4.5 micro-C charge moves 6.0 m in the positive x direction, and to find the electric potential energy (which is -11 J), does my equation look like this:

Electromagnatism Induction of a Metal Bar

A metal bar with length L, mass m, and resistance R is placed on frictionless, metal rails that are inclined at an angle (Data) above the horizontal. The rails have negligible resistance. A uniform magnetic field of magnitude B is directed downward. The bar is released from rest and slides down the rails. a) Is the direction

Equilibrium state of a mixture.

Question: Three liquids are at temperatures of 10 degrees C, 20 degrees C and 30 degrees C, respectively. Equal masses of the first two liquids are mixed, and the equilibrium temperature is 17 degrees C. Equal masses of the second and third are then mixed, and the equilibrium temperature is 28 degrees C. Find the equilibri

After a block and marble collide, the block executes SHM

A spring with negligible mass, and force constant k= 60 nt/m, has one end fixed, and the other end attached to a stationary block of mass M= 2.0 kg on a horizontal, frictionless table. At time t=0, a ball of mass m= .25 kg, with horizontal speed of Vb= 50 m/sec to the right before impact, hits the block and bounces off, then

Energy density in an electric field

A charge isolated metal sphere of diameter 10cm has a potential of 8000 V relative to V=0 at infinity. Calculate the energy density in the electric field near the surface of the sphere?

Energy Absorbance

A film badge worn by a radiologist indicates that she has received an absorbed dose of 2.3e-5 Gy. The mass of the radiologist is 67 kg. How much energy has she absorbed? Answer in mJ.

What is the Activity N//t of the Radioactive Source?

A 2.0-kg tumor is being irradiated by a radioactive source. The tumor receives an absorbed dose of 12 Gy in a time of 750 s. Each disintegration of the radioactive source produces a particle that enters the tumor and delivers an energy of 0.35 MeV. What is the activity N//t of the radioactive source?