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1. Pendulum beam Problem

Homework Statement On the construction site for a new skyscraper, a uniform beam of steel is suspended from one end. If the beam swings back and forth with a period of 1.10 s, what is its length? Homework Equations T=2*pi*sqroor (L/g) The Attempt at a Solution...
2. Revolutions of an electron

Homework Statement A hydrogen atom exists in an excited state for typically 5.79 ns. How many revolution would an electron make in the n=2 state before decaying? Homework Equations L=m*v*Rn=h(bar)*n w=v/Rn Rn=n^2*Ao Ao=.053 nm The Attempt at a Solution Rn=4*.053=.212 nm...
3. A protons Min KE

Homework Statement A proton is confined in a uranium nucleus of radius 7.41 fm. Determine the proton's minimum kinetic energy K less than or equal to delta K according to the uncertainty principle if the proton is well approximated by a Gaussian wave packet confined by the nuclear diameter...
4. Normalization Constant A

Homework Statement The wave function of a particle is Y(x,t) = A e^-kx*e^-iwt for x greater than or equal too 0, and it is zero everywhere else. What is the numerical value of the normalization constant A for k=5.55 1/nm and w =7.19 1/ps? Homework Equations intergral Y^2=1 The...
5. Crazy dude jumping on a Merry-Go-Round

Homework Statement A disk-shaped merry-go-round of radius 2.63 m and mass 155 kg rotates freely with an angular speed of 0.686 rev/s. A 59.4 kg person running tangential to the rim of the merry-go-round at 3.99 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the...
6. Crane lifting crate

Homework Statement The crane shown in the drawing is lifting a 186-kg crate upward with an acceleration of 2.0 m/s2. The cable from the crate passes over a solid cylindrical pulley at the top of the boom. The pulley has a mass of 130 kg. The cable is then wound onto a hollow cylindrical drum...
7. Walking on a canoe, finding its mass.

Homework Statement A 61.7 kg canoeist stands in the middle of her canoe. The canoe is 3.9 m long, and the end that is closest to land is 2.5 m from the shore. The canoeist now walks toward the shore until she comes to the end of the canoe. Suppose the canoeist is 3.4 m from shore when she...
8. Elastic non head on Collision

Homework Statement A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle Theta2 = 45° from the neutron's initial direction. The neutron's initial speed is 6.6x 10^5 m/s...
9. Raising a Bucket out of a Well

Homework Statement You raise a bucket of water from the bottom of a deep well. If your power output is 104 W, and the mass of the bucket and the water in it is 6.00 kg, with what speed can you raise the bucket? Ignore the weight of the rope. Homework Equations P=W/t W=P*t...
10. Pair-Production problems

Homework Statement How much photon energy would be required to produce a proton-antiproton pair? Give the answer in SI units. Homework Equations E^2=p^2c^2+m^2c^4 E=pc+pc p=mc E=2*m*c^2 The Attempt at a Solution I seem to be confused I know the KE would be zero I also know this...
11. Electron in an electirc field.

Homework Statement Across what potential difference does an electron have to be accelerated in order to reach speed v=1.80×106 m/s? Homework Equations I checked to see if relitivity was important and it was not E=.5 m v^2=eV The Attempt at a Solution I dunno if I am...
12. Meteorite falling on a Car

Homework Statement A 27 pound meteorite fell and struck a car, creating a dent about 28 cm deep. If the initial speed of the meteorite was 530 m/s, what was the magnitude of the average force exerted on the meteorite by the car? Homework Equations Vf^2=Vi^2+2ad F=ma The Attempt at...
13. Bicycle coasting up a Hill

Homework Statement Coasting along at 7.10 m/s, a 60.0 kg bicyclist on a 7.60 kg bicycle encounters a small hill. If the speed of the bicyclist is 6.00 m/s at the top of the hill, how much work was done on the bicyclist and her bike? Homework Equations KEf-KEi=W .5mvi^2-.5mvf^2...
14. How much ice must melt at 0 deg. C to gain 6 g of mass?

1. Homework Statement This is all that is given. How much ice must melt at 0 deg. C to gain 6 g of mass? 2. Homework Equations I don't know any Relevant equations to this problem. 3. The Attempt at a Solution I have tried leaving mass as a variable and using Latent Heat...
15. How much ice must melt at 0 deg. C to gain 6 g of mass?

Homework Statement This is all that is given. How much ice must melt at 0 deg. C to gain 6 g of mass? Homework Equations I don't know any Relevant equations to this problem. The Attempt at a Solution I have tried leaving mass as a variable and using Latent Heat Energys too. I...
16. Torque Help

I don't understand these concepts very well. Could someone please take the time and help run through a few of these problems. I don't want the answers I wanna know how to get them. Any help would be appreciated, thanks. 1. Two builders carry a sheet of drywall up a ramp. Assume that...