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)
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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
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
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.
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)
A Desert Eagle chambered for 44 mag in effect launches a bullet from a compressed slide spring (the bullet develops full velocity as the spring develops full compression). If the bullet is 180 grain (11.67 grams) and has a muzzle velocity of 1450 fps (442 m/s), assuming kinetic energy is conserved, what is the spring constant of
Hi. Can someone please show me how to do the following problem? I am not too sure how to approach it. Question: Given an RL circuit in which there's a 9.0 V battery, R = 5.5 ohms, L = 6.1 mH, and there's a switch that can be opened or closed, how much energy is stored in the inductor after the switch has been closed a long t
Does the electric field only move in the + ---> - direction? Or does it depend on the charge, so that the electric field moves in a + ---> - direction for a + charge and moves in the - ---> + direction for a - charge? In the latter case, if a + charge is moving toward the - plate of a capacitor, is its direction negative sinc
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:
Show that for a mixture of two gases at the same temperature, the ratio of the rms speeds of their molecules is equal to the inverse ratio of the square roots of their molecular masses.
Spring S has a relaxed length of s= .85 m and has a force constant ks= 24 nt/m. Spring P has a relaxed length p= .45 m and has a force constant ks= 60 nt/m. Initially, each spring has one end attached to opposite sides of a box so that the distance between their free ends is d= .70 m apart. Their ends are pulled toward each ot
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
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
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
Using Bohr Model determine: 1. Energy loss when electron moves from orbit n=3 to n=1 2. Calculate wavelength of the light when electron moves orbit from n=3 to n=1.
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?
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.
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?
The K characteristic X-ray line for tungsten has a wavelength of 1.84 10-11 m. What is the difference in energy between the two energy levels that give rise to this line? Express in joules and eV.
A proton is located at a distance of 0.410 m from a point charge of +8.30 µC. The repulsive electric force moves the proton until it is at a distance of 1.56 m from the charge. Suppose that the electric potential energy lost by the system is carried off by a photon that is emitted during the process. What is its wavelength?
How close would two stationary electrons have to be positioned so that their total mass is 8 times what it is when the electrons are very far apart?
Calculate the classical frequency for the light emitted by an atom. To do so, note that the frequency of revolution is v/2pir, where r is the Bohr radius. Show that as n approches infinity in f= 2pi2mk2e4/h3 times 2n-1/(n-a)2 n2 the expression varies as 1/n3 and reduces to the classical frequency.
For two distinguishable, non-interacting particles in a box, Quantum Mechanics says the energy must be, for each individual particle, E = (h^2)/(8mL^2)*[(n_x)^2 + (n_y)^2 + (n_z)^2) where L is the length of one side of the cube, m is the mass of the particle, and the n's are independent integers that can take any value fr
Please see the attached file for full problem description. --- A child's pogo stick stores energy in a spring with a force constant of 2.50 x 10^4 N/m. At position A (XA= -0.100 m), the spring compression is a maximum and the child is momentarily at rest. At position B (Xb=0) the spring is relaxed and the child is moving u
Trying to visualize this scenario so I can draw a picture, but I am drawing a blank. I think that I have to use the mgh equation and mv^2/r equation. Also, do you think you could offer some additional questions that might be relevant to this problem so I can practice. See attached file for full problem description.
In a vertical plane, a uniform sphere, mass m, radius r, released from rest at a point h meters above ground level, rolls without slipping down a straight section of track then around the inside of a circular track of radius R. Given R>>r. Find the minimum initial height h, such that the sphere barely maintains contact at th
A cart has four wheels in the shape of uniform cylinders, each of whose mass is m= 20 kg. The total mass of the cart, including the cylinders, is M= 1000 kg. The total KE (kinetic energy) of the cylinders is what percentage of the total KE of the moving cart?
As Fig. 8-44 shows, a 4.5 kg block is accelerated by a compressed spring whose spring constant is 640 N/m. After leaving the spring at the spring's relaxed length, the block travels over a horizontal surface, with a coefficient of kinetic friction of 0.25, for a distance of 5.9 m before stopping. (a) What is the increase in
The only force acting on a 2.4 kg body as it moves along the x axis varies as shown in Fig. 7-33 (attached). The velocity of the body at x = 0 is 4.0 m/s. (a) What is the kinetic energy of the body at x = 3.0 m? (b) At what value of x will the body have a kinetic energy of 8.0 J? (c) What is the maximum kinetic energy attai