Physics - December 2007

A box rests on the (horizontal) back of a truck. The coefficient of static friction between the box and the surface on which it rests is 0.24 while the coefficient of kinetic friction is 0.12. What maximum distance can the truck travel (starting from rest and moving horizontally with constant acceleration) in 3.0 s without having the box slide?

2007-12-06 16:35:17 · 5 answers · asked by roncho 4

Behave like a single, moving magnet, as in generating an current in a wire, etc? Assuming they were close enough together, and energized in rapid succession? A series of electromagnets wouldn't experience the 'drag' that a moving magnet would since there's no motion. Would the electrons in the wire be 'fooled'?

2007-12-06 16:33:18 · 1 answers · asked by AmigaJoe 3

It takes 210 cal to raise the temperature of 340 g of lead from 0 to 10 C. What is the specific heat of lead?

2007-12-06 16:32:44 · 1 answers · asked by jim m 3

in a distant galaxy, they see a sudden, simultaneous rise in visible light and other forms of electromagnetic radiation. Is this evidence to support the idea that the speed of light is independent of frequency?

2007-12-06 16:29:37 · 1 answers · asked by Monkjitsu 1

A carnival Ferris wheel has a 15-m radius and completes five turns about its horizontal axis every minute. What is the acceleration of a passenger at his or her lowest point during the ride?

2007-12-06 16:18:38 · 5 answers · asked by roncho 4

A liquid ( = 1.65 g/cm3) flows through two horizontal sections of tubing joined end to end. In the first section the cross-sectional area is 10.0 cm2, the flow speed is 265 cm/s, and the pressure is 1.20 105 Pa. In the second section the cross-sectional area is 2.50 cm2. Calculate the smaller section's pressure.

2007-12-06 16:05:13 · 1 answers · asked by shalini p 1

2007-12-06 15:49:22 · 4 answers · asked by Anonymous

a uniform beam weighs 500N and is 2.00m long. it supports a load of 700N. the beam is attached to the vertical wall by a hinge and a cable. the length from the hinge to the cable is 0.4L and from the cable to the load is 0.6L. the angle is 55 degree.
a. find the tension in the cable
b. find the net force exerted by the hinge on the steel bar, and the angle it makes with horizontal axis.

2007-12-06 15:45:08 · 1 answers · asked by Neha G 1

2007-12-06 15:32:48 · 6 answers · asked by Anonymous

After being pushed and released, a 50kg crate slides across a factory floor. Friction on the sliding crate is 200N. what is the crate's acceleration?


what are the equations and steps to find the answer?

2007-12-06 15:18:46 · 3 answers · asked by Catherine 2

If a person is in a car starts driving at the constant speed V. If a sled is at rest at the top of a slope, it has some potential energy. Once it rolls down the hill, it has kinetic energy, while moving at the same constant speed V. , how is that from the reference frame of the car, Kinetic Energy = 0, thus, ME initial is not = to ME final, violating newton's law.

2007-12-06 14:55:43 · 1 answers · asked by Fantasy Football Guru 27 3

We've started Circular Motion in physics but I don't understand the concept even after reading the book.please can someone explain how to do this problem?

The lazy susan has been rotating for some time in this problem at a constant angular frequency of 2 sec^-1. At this moment the position of A and B are given as: r(a)=.5 m @ 180 (degrees) and r(b)=.25 m @ 270 (degrees)
(a) At this moment what are the velocities of cans A and B?
can A ___m/s @ ___degrees
can B ___m/s @ ___degrees
(b) At this moment what are the accelerations of cans A and B?
can A ___m/s^2 @ ____degrees
can B ___m/s^2 @ ____degrees
(c) What is the period and frequency for can B?
T= ___sec
f= ___sec^-1
(d) In one second what will be the position, velocity, and acceleration of can B?
r= ___m @ ___degrees
v= ___m/s @ ___degrees
a= ___m/s^2 @ ___degrees
Also, please please show all work with all equations used
Thanks a lot for your help =

2007-12-06 14:40:48 · 2 answers · asked by Kamal 2

science stuff

2007-12-06 14:38:00 · 3 answers · asked by rosie cheeks 2

2007-12-06 14:33:02 · 5 answers · asked by Mcky R 2

If a leaf is to maintain a temperature of 50°C (reasonable for a leaf), it must lose 250 W/m2 by transpiration (evaporative heat loss). Note that the leaf also loses heat by radiation, but we will neglect this. How much water is lost after 1 h through transpiration only? The area of the leaf is 0.006 m2.

Grams.

i thought it was 16.2 but it wasnt right

2007-12-06 14:29:36 · 1 answers · asked by Anonymous

A satellite experiences a gravitiational force of 228N at an altitude of 4.0 x 10^7m above the earth. What is the mass of the satellite?

I do 228 = GMm/(4x10^7 x 6x10^6)^2 (and solving for m) and that's not the right answer.... so what should I be doing?

2007-12-06 14:23:53 · 2 answers · asked by Maike Tater 2

An ideal gas system undergoes an isovolumetric process in which 20 J of energy is added as heat to the gas. What is the change in the system’s internal energy?

2007-12-06 13:54:59 · 1 answers · asked by thisisjakethomas 1

2007-12-06 13:53:09 · 3 answers · asked by fade 3

2007-12-06 13:40:07 · 4 answers · asked by timmee91 1

Two point charges are separated by 6 cm. The attractive force between them is 30 N. Find the force between them when they are separated by 24 cm.

2007-12-06 13:02:46 · 1 answers · asked by maggiegd05 1

2007-12-06 13:01:02 · 1 answers · asked by maggiegd05 1

Hey! I've been trying to work on this vectors worksheet lately. Here it is:

1. http://img205.imageshack.us/img205/9427/70466397yk4.jpg
2. http://img490.imageshack.us/img490/2572/58282826kh9.jpg
3. http://img490.imageshack.us/img490/8449/72000225yt9.jpg

I got many answers, but I was unable to do (or was not sure about) the ones with stars next to them (#4, 7, 10, 12, 14, and 20). I'd really appreciate if someone explained them to me. Also, if someone has the time, and heart to look over my other answers and tell me if I'm correct or not, I'd be more than grateful.

Thanks for any help! :]

2007-12-06 12:45:07 · 1 answers · asked by Anonymous

The flywheel has mass 39.0 kg and diameter 78.0 cm. The power is off for 28.0 s and during this time the flywheel slows due to friction in its axle bearings. During the time the power is off, the flywheel makes 180 complete revolutions. At what rate is the flywheel spinning when the power comes back on? How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on? How many revolutions would the wheel have made during this time?

2007-12-06 12:33:20 · 2 answers · asked by coolredturtle1555 2

A man holding a gun ((mass of man)+(mass of gun)+(mass of bullet)=60kg)) skates on frictionless ice at an initial speed of +2 m/s and fires a 100 gram bullet with a speed of +500 m/s from the gun.

a) What is the speed of the man after firing the gun? (be sure to include +/- direction)

b) What is the initial total energy of the man-gun-bullet system (before the bullet is fired)? What is the final total energy of the man-gun-bullet system (just after the bullet is fired)?

c)is this an example of an elastic, inelastic, or perfectly inelastic collision, and why?

2007-12-06 12:05:54 · 1 answers · asked by Kevin 1

2007-12-06 12:05:01 · 3 answers · asked by flirty423 1

A spinning bicycle wheel 65.0 cm in diameter is rotating at 2.00 rev/s and comes to rest in 15.0 s
(a) What is the angular acceleration of the wheel?
(b) If the wheel has a mass of 1.75 kg, what frictional force in its bearing has caused it to stop?

2007-12-06 11:40:32 · 1 answers · asked by Anonymous

A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 85.0 cm. If its speed is 3.25 m/s and its mass is .335 kg, calculate the tension in the string when the ball

is at the top of it's path

and at the bottom of the path?

i think i got the right anwser but not completely sure plz help!

2007-12-06 11:31:51 · 1 answers · asked by Anonymous

2007-12-06 11:10:26 · 2 answers · asked by Soni 2

The rotor has a Radius of 6m. If the Ride spins @ 20m/s, what is the minimum coefficient of friction that must exist between a rider and the wall?
[Fc is caused by Fnorm in this problem, therefore
Fc=Fnorm]

2007-12-06 11:01:21 · 2 answers · asked by alex s 1

if the area of the top is 0.2m^2?

2007-12-06 10:54:20 · 2 answers · asked by mjm13186 2