Physics - November 2007

A worker transports bricks from a pile to the endgate of a pick-up truck, and then pushes the bricks to the front of the truck’s bed.

Is work being done in each of the steps, and if so, please explain (I know work is being done, but I don't know how to explain it other than saying the worker did work)

2007-11-20 15:54:59 · 3 answers · asked by Scout F 2

submerged in water. What is the density of the object?

Density of water = 1000 kg/m^3

2007-11-20 15:23:39 · 4 answers · asked by Pascal 4

Is it possible to force with strength two North(or south) poles of two separate magnet to be touching each other ?
If yes what will happen if we release them from touching ?

2007-11-20 15:21:58 · 11 answers · asked by karta s 2

Please tell me if the affects to the human body from exposure to Beta radiation is the same as Alpha or Gamma radiation. If it is not, then please describe the effects of Beta radiation.

2007-11-20 15:20:42 · 2 answers · asked by Asian Boy 2

A 0.187 kg mass is attached to a spring and executes simple harmonic motion with a period of 0.27 s. the total energy of the system is 2.5 J. Find the force constant of the spring.

2007-11-20 15:20:23 · 2 answers · asked by Yami 1

2007-11-20 15:11:05 · 5 answers · asked by Anonymous

2007-11-20 15:04:35 · 6 answers · asked by tyar 2

2007-11-20 14:56:51 · 4 answers · asked by Baby Gurl 1

2007-11-20 14:55:16 · 5 answers · asked by klyre s 1

A machine gun is attached to a railroad flat car that rolls with negligible friction. If the railroad car has a mass of 6.25 X 10 to the 4th power kg, how many bullets of mass .025 kg would have to be fired at 250 m/s off the back to give the railroad car a foward velocity of .5 m/s?
A. 400
b 2000
c 3000
d 5000

2007-11-20 14:41:04 · 1 answers · asked by S.I.N 4

physics help!

2007-11-20 14:34:19 · 4 answers · asked by crystalclear72000 1

A water tank open to the atmosphere at the top has two holes punched in its side, one above the other. The holes are 4.00 cm and 14.3 cm above the floor. How high does water stand in the tank if the two streams of water hit the floor at the same place?

2007-11-20 14:15:21 · 4 answers · asked by limeinelcoconut 1

I have no idea how to solve this so please just solve it for me. 10 points for the first person to solve it with proof of correct answer... thanks.
Performance (with standard 660 grain bullet)
Muzzle Velocity 2,800 fps (853 mps)
Muzzle Energy 11,500 foot-pounds (15,582 J)
Maximum Range 7,450 yd (6,812 m)
Maximum Effective Range 2,000 yd (1,829 m)
Question is How long will it take the bullet to reach a target at 2,000 yards assuming 0 mph wind
Thank you in advance.

For those of you wondering... this is for a poster and the only piece I am missing is the seconds it takes.

2007-11-20 13:48:59 · 1 answers · asked by huntnikk2000 3

I always need help working out physics problems... would appreciate it...

The earth and moon are separated by a center-to-center distance of 3.85 x 10^8 m. The mass of the earth is 5.98 x 10^24 kg and that of the moon is 7.35 x 10^22 kg. How far does the center of mass lie from the center of the earth? (Chapter 7)

2007-11-20 13:41:40 · 1 answers · asked by PinkyTrauma 2

More physics questions I need help with..

A Ferris wheel rotates at an angular velocity of 0.24 rad/s. Starting from rest, it reaches its operating speed with an average angular acceleration of 0.030 rad/s^2. How long does it take the wheel to come up to operating speed? (Chapter 8)

2007-11-20 13:40:59 · 2 answers · asked by PinkyTrauma 2

I need help with physics and I'll ask a million more trust me.

A motorcyclist is traveling along a road and accelerates for 4.50 s to pass another cyclist. The angular acceleration of each wheel is +6.70 rad/s^2, and, just after passing, the angular velocity of each is +74.5 rad/s, where the plus signs indicate counterclockwise directions. What is the angular displacement of each wheel during this time? (Chapter 8)

2007-11-20 13:40:27 · 2 answers · asked by PinkyTrauma 2

I need helping working out Physics problems once again..

A string weed trimmer utilizes a length of nylon string that rotates about an axis perpendicular to one end of the string. The string rotates at an angular speed of 47 rev/s, and its tip has a tangential speed of 54 m/s. What is the length of the rotating spring? (Chapter 8)

2007-11-20 13:39:35 · 1 answers · asked by PinkyTrauma 2

A 20.0kg floodlight in a park is supported at the end of a horizontal beam of negligeble mass that is hinged to a pole. A cable at an angle of 30 degrees witht the beam helps to support the light. Find (a) the tension in the cable and (b) the horizontal and veritical forces exerted on the beamm by the pole.

Pls. explain how to do it!

Answers:
a)392N
b)H:339N (to right)
V:0

2007-11-20 13:24:12 · 2 answers · asked by boy101 3

Note: Take East as the positive direction.
A 85kg fisherman jumps from a dock into a 130kg rowboat at rest on the West side of the dock.
If the velocity of the fisherman is 5.5m/s to the West as he leaves the dock, what is the final velocity of the fisherman and the boat? Answer in units of m/s.

Please help me with this, i cant figure it out, thanks in advance.

2007-11-20 13:22:15 · 4 answers · asked by Anonymous

A 12kg child on a playground swing moves with a speed of 7.5m/s when the 9m long swing is at its lowest point and the acceleration of gravity is 9.8m/s^2. How can I find the angle that the swing makes with the vertical when the swing is at its highest point?

2007-11-20 13:10:29 · 1 answers · asked by Shane 1

:)
In every direction

2007-11-20 13:07:14 · 2 answers · asked by Nina Lista 1

A supertrain of proper length 190 m travels at a speed of 0.9c as it passes through a tunnel having proper length 90 m. How much longer is the tunnel than the train or vice versa as seen by an observer at rest with respect to the tunnel?

the answer is in meters

2007-11-20 13:00:38 · 2 answers · asked by Anonymous

2007-11-20 12:50:58 · 5 answers · asked by STUDY 3

A 56.0 kg ballet dancer stands on her toes during a performance with four square inches (26.0 cm2) in contact with the floor. What is the pressure exerted by the floor over the area of contact in the following cases?(a) if the dancer is stationary(b) if the dancer is leaping upwards with an acceleration of 5.00 m/s2

2007-11-20 12:45:18 · 1 answers · asked by Anonymous

an ideal spring of unstretched length .2 m is on a frictionless table. One end is fixed on wall and other is attached to mass M=8kg. M is attached to string over pulley and block of mass m=4kg hangs from other end of string. In equilibrium, length of spring is .25m and m is .7m above the floor.
Calculate tension in string
Calculate force constant of spring

2007-11-20 12:45:07 · 1 answers · asked by rachhar123 1

2007-11-20 12:42:27 · 3 answers · asked by STUDY 3

2007-11-20 12:41:06 · 1 answers · asked by hulkholgan21 1

A 71.0 kg diver steps off a diving board and drops straight down into the water. The net force when in the water is an upward 1440 N. If the diver comes to rest 4.7 m below the water's surface, what is the total distance between the diving board and the diver's stopping point underwater?

(answer in meters)

2007-11-20 12:33:15 · 1 answers · asked by JJ 1

A 60 kg ice skater moving to the right with a velocity of 3m/s throws a 0.150 kg snowball to the right with a velocity of 30m/s relative to the ground.
What is the velocity of the ice skater after throwing the snowball? Disregard the friction between the skates and the ice. Answer in units of m/s.
-----------------------------------------------------------------------------------
A second skater initially at rest with a mass of 58kg catches the snowball.
What is the velocity of the second skater after catching the snowball in a perfectly inelastic collision? Answer in units of m/s


Help on this would be much appreciated, thanks in advance!!!

2007-11-20 12:33:14 · 1 answers · asked by Anonymous

2007-11-20 12:32:16 · 1 answers · asked by Kiko Z 1