Recent content by confused1

How much work (in electron volts) must be performed by an external force to bring in another proton (from very far away) to the "surface" of the nucleus? (Ignore the effects of the electron.) HELP: Find the change in electric potential when proton is moved from very far away to the surface...

Lasers are now used in eye surgery. Given that the wavelength of a certain laser is 514 nm and the power of the laser is 1.9 W, how many photons are released if the laser is used for 0.052 s during the surgery? HELP: You know the energy released per second (the power) and the time the laser...

A hydrogen nucleus has a radius of 1 x 10-15 m and the electron is about 5.4 x 10-11 m from the nucleus. Assume the hydrogen atom is a ball with a radius of about 5.4 x 10-11 m and the nucleus is a ball with a radius of 1 x 10-15 m. How much work (in electron volts) must be performed by an...

A copper wire has a resistance of 0.501 ohms at 20.0 degrees C, and an iron wire has a resistance of 0.487 ohms at the same temperature. At what temperature are their resistances equal? Resistivity of Copper: .0039 Resistivity of Iron: .0005

A charge of -3.4 × 10-9 C is at the origin and a charge of 6.9 × 10-9 C is on the x-axis at x = 3 m. At what location on the x-axis is the electric field zero? HELP: Which region is the only possible one where the E-field could be zero (to the left of Q1, in between the charges, or to the...

Four charges are placed on the corners of a rectangle. What is the resultant force on the positive charge (a = 1.3 m, b = 0.8 m, q = 1.8 × 10-9C)? HELP: Use Coulomb's law and superposition. HELP: Superposition tells us that we can find the force on the positive charge by looking at the...

Finally, your friend's twin engine jet airplane lands. As it stands on the runway, you hear the sound of the engines getting louder and softer, rhythmically once every two seconds. The average frequency you hear is 4100 Hz. What is the difference between the individual frequencies of the sounds...

Finally, your friend's twin engine jet airplane lands. As it stands on the runway, you hear the sound of the engines getting louder and softer, rhythmically once every two seconds. The average frequency you hear is 4100 Hz. What is the difference between the individual frequencies of the sounds...

Ultrasound reflected from an oncoming bloodstream that is moving at a 30 cm/s is mixed with the original frequency of 2.5 MHz to produce beats. What is the beat frequency? (Velocity of sound in blood = 1540 m/s.) Beat Frequency in Hz =

If a large housefly 3 m away from you makes a noise of 40 dB, what is the noise level of 1000 flies at that distance, assuming interference has a negligible effect? Noise level of 1000 flies = ?

Ultrasound reflected from an oncoming bloodstream that is moving at a 30 cm/s is mixed with the original frequency of 2.5 MHz to produce beats. What is the beat frequency in Hz? (Velocity of sound in blood = 1540 m/s.)

a) What is the net displacement Delta x of the spring from its former equilibrium position? What force F was required to compress the springs? The effective spring constant is the ratio F/(delta x).

A platform of mass 0.8 kg is supported on four springs (only two springs are shown in the picture, but there are four altogether). A chunk of modeling clay of mass 0.6 kg is held above the table and dropped so that it hits the table with a speed of v = 0.9 m/s. The clay sticks to the table...

T = 2*pi / w. What is w for a simple pendulum?

A pendulum has a period of 1.8 s. a) Its mass is doubled. What is its period now? b) Its length is doubled. What is its period now? The original pendulum is taken to a planet where g = 16 m/s2. c) What is its period on that planet?