Physics - July 2007

Our physics teacher just asked this question in class. And I'm pretty sure it is possible.Acceleration is given by the formula v-u/t.
But if the sum (v-u) is not zero then acceleration cannot be zero!
Please, I need detailed answers.Just the example won't do.

2007-07-29 23:06:05 · 13 answers · asked by Anonymous

2007-07-29 22:57:42 · 4 answers · asked by Akilesh - Internet Undertaker 7

2007-07-29 22:37:06 · 8 answers · asked by Vernix Lanugo 3

I've read that when in the process of making home made ice cream we use salt to lower the temperature of the ice. I understand it lowers the temperature of the ice sunstantially.
My Question:
Will salt water or brine freeze in a home freezer?

Will it reach a lower temperature?....and would that ice melt more slowly at room temperature than ice made of pure water?

2007-07-29 22:32:13 · 2 answers · asked by ericbryce2 7

A car of mass 1000 kg is being towed on level ground by a van of mass 2000 kg. There are constant retarding forces (due to air resistance and friction) on both the car and the van. The car force on the car is 300 N; on the van it is 500 N.

1) What is the size of the force due to the van's wheels that pushes the van forwards?

2) What is the size of the tension T in the towbar?

3) When the two vehicles are travelling at 15 m/s, the van driver disconnects the motor from the driving wheels, and the van and the car slow down at a constant rate due to the constant retarding forces acting on the vehicles. How far do the two vehicles travel before coming to rest?

Can u explain it so I understand it? Thanks!

2007-07-29 22:07:27 · 3 answers · asked by Anonymous

Two blocks (1st 1 from left to right 25kg, 2nd one 5kg) are connected by a cord on a horizontal. A force of 120N pulls on the blocks towards the right. Find the acceleration of the blocks and the tension in the connecting cord if (a) the surface is frictionless, and (b) the coefficient of kinetic friction is 0.20

2007-07-29 20:36:58 · 3 answers · asked by Mafia Agent 4207 5

"A 5.2 kg stone is tied to a 4.7 m long string and swung around a circle at a constant angular velocity 7.6 1/s. Find the magnitude of the torque about the origin."
Torque is Inertia*angular acceleration, so 5.2kg*(4.7m)^2*7.6rad/s^2, it was 872.9968 but it's not correct. What did I make a mistake? Please explain to me. Thank you.

2007-07-29 20:31:10 · 2 answers · asked by Anonymous

2007-07-29 20:19:15 · 3 answers · asked by Navdeep D 1

2007-07-29 20:07:32 · 12 answers · asked by Anonymous

2007-07-29 20:05:49 · 3 answers · asked by bern 1

An ideal gas is in contact with a heat reservoir so that it remains at a constant temperature of 300 K. The gas is compressed from a volume of 29 L to a volume of 17 L. During the process the mechanical device pushing the piston to compress the gas is found to expend 5 kJ of energy. What is the magnitude of the heat flow between the heat reservoir and the gas and in what direction does the heat flow occur?

2007-07-29 20:01:00 · 3 answers · asked by Sandesh R 1

A diver rises quickly to the surface from a 8-m depth. If she did not exhale the gas from her lungs before rising, by what factor would her lungs expand? Assume the temperature to be constant and the pressure in the lungs to match the pressure outside the diver's body. The density of seawater is 1.03 times 103 kg/m3.

2007-07-29 19:56:16 · 2 answers · asked by Sandesh R 1

3 Questions, an answer to any would be great.

1. How fast does heat conduct in air?
2. How many times faster does heat conduct in water than air?
3. How many times faster does heat conduct in a solid than in air? (eg a plank of wood and a piece of metal)

2007-07-29 19:41:16 · 6 answers · asked by C4 Snake 3

pinhole camera..................move a pinhole camera closer to or farther from a lamp...waht do you observe on the screen?how would you explain it?
do you think you can make the image on the screen in other positions?HOW?

2007-07-29 19:26:29 · 1 answers · asked by Kauori 1

"A thin disk, mounted on a frictionless vertical shaft of negligible rotational inertia, is rotating at 636 revolutions per minute. An identical disk (that is not initially rotating) is dropped onto the first disk. The frictional force between the disks causes them to rotate at a common angular velocity. Find this common angular velocity. NOTE: Be careful with your units!"
Since it is stated that there is no moment of inertia, the common angular velocity is the same as the first velocity which is 66.6 rad/s (converted it into radian/s). If this is not correct, please explain to me. Thank you.

2007-07-29 19:17:13 · 2 answers · asked by Anonymous

I'm pretty sure that I understand the concept, but I'd like to be sure about this. My question pertains to how gravity increases as the mass of an object is compacted into a smaller and smaller space (i.e. a black hole). Does the gravity increase because the space-time distortion becomes steeper and steeper as the object becomes smaller?

This is how I'm picturing it (though its probably way out of scale!). Say there is an object that is as large as the center of a plate that has a mass of x which distorts space-time to a curvature equal to the curved edges of a plate. As one may clearly see this is not too steep of a curvature. On the other hand, if an object such as a shot glass has the same mass of x and is the size of the bottom of the shotglass then the space-time distortion of the object is equal to the sides of the glass. Thus, the shotglass object requires more energy to escape from inside of the glass than the energy required for an object to escape the plate. Am I correct?

2007-07-29 19:14:38 · 3 answers · asked by bobo! 1

In a nozzle the velocity is incresed with the expense of pressure.

2007-07-29 18:41:52 · 3 answers · asked by nish 1

Hey guys, I have a wormhole in my utility room that I'm having trouble getting rid of.

I'm come upon this conclusion by the following observations: Over the last couple of years, I have purchased at least a hundred pairs of socks. Once those socks have entered my house, I have never removed them from my home. Yet somehow my collection has been reduced to about a dozen socks, and not a single one has a match.

I have observed that the discrepancy occurs in my utility room. Whenever I bring socks to the washer, I always put in more socks than I take out. There isn't nearly enough lint on the lint tray to account for this discrepancy, so I have concluded that there must be a wormhole.

I have tried various methods of removing the wormhole, but none have succeeded. If anyone can help, it would be much appreciated.

2007-07-29 17:20:49 · 4 answers · asked by David H 1

2007-07-29 16:47:33 · 2 answers · asked by Kel 1

I'm considering ordering one so just wondering. I appreciate it if you're actually knowledgable and have sources, thanks!

2007-07-29 16:11:54 · 4 answers · asked by ? 3

2007-07-29 15:27:34 · 9 answers · asked by ? 2

2007-07-29 15:24:31 · 3 answers · asked by Anonymous

2007-07-29 15:15:12 · 7 answers · asked by jr 2

A heating element in a stove is designed to dissipate 2600 W when connected to 240 V. Assuming that the resistance is constant, calculate the current in this element if it is connected to 120 V.

How do I solve this? Thanks in advance.

2007-07-29 14:27:27 · 4 answers · asked by protege moi 3

an oscilloscope is used to make some basic electrical measurements the range knob settings are : veritcal 2 V/cm horizontal 5 msec/cm the trough to crest height of the sine wave is 7.4 cm the crest to crest length along te time axis is 4.8 cm

calulate the peak to peak voltage, the peak voltage, and the rms voltage

and also the period and frequency of the wave

2007-07-29 13:36:42 · 1 answers · asked by Anonymous

How come we speak English because of polarized light?

2007-07-29 13:14:45 · 5 answers · asked by Anonymous

What is the total velocity of the plane
formula n xplain

2007-07-29 13:12:06 · 3 answers · asked by xplicit 2

With a possible example, thank you.

2007-07-29 13:08:06 · 3 answers · asked by Anonymous

1. If the velocity of a particle is zero, can its acceleration be non-zero?

2. Can an object having constant acceleration ever stop and stay stopped?

2007-07-29 11:42:17 · 8 answers · asked by Heller 2

How does this contribute to our current acceptance of plate tectonic theory

2007-07-29 11:21:06 · 2 answers · asked by Anonymous