Physics - November 2007

A large object previously floating on the surface of an ocean is caused to sink. Does it always sink to the bottom or might it find a depth in the ocean where it can float once again?

2007-11-17 11:28:10 · 13 answers · asked by Grant V 1

2. A flight attendant pulls her 70 N flight bag a distance of 253 m along a level airport floor at a constant velocity. The force she exerts is 40 N at an angle of 52 above the horizontal. Find the following:
a. The work she does on the flight bag
b. The work done by the force of friction on the flight bag
c. The coefficient of kinetic friction between the flight bag and the floor.

Please show work and explain to me how to do it. Thank you.

2007-11-17 11:23:27 · 3 answers · asked by James J 1

What is the de Broglie wavelength of an electron that strikes the back of the face of a TV screen at 1/10 the speed of light?
_____m

2007-11-17 10:41:02 · 4 answers · asked by w_rayas07 1

M2 = 153.0 kg, which is initially at rest on a frictionless surface. The spring has a spring constant k = 1640 N/m. What is the maximum compression of the spring?

2007-11-17 10:22:38 · 2 answers · asked by MeDIGURU 1

two identical small spheres of negligible mass. are separated by a centre to centre distance of 2 meters. The force between them is 6 N. calculate the charge on each sphere.

answer: 1.3 x 10^(-4)

2007-11-17 10:14:56 · 1 answers · asked by bhavin p 1

(hence it can go 186,000 miles per second instantaneously without acceleration) then how can it provide a "push" for instance on solar sails in space. How can mere energy "push" or apply a physical force on matter?

2007-11-17 09:52:32 · 3 answers · asked by Anonymous

2007-11-17 09:43:34 · 8 answers · asked by Anonymous

2007-11-17 09:42:28 · 4 answers · asked by whoopsidaisy 3

2007-11-17 09:19:15 · 4 answers · asked by Anonymous

An insulated beaker with negligible mass contains liquid water with a mass of 0.240 kg and a temperature of 65.9 C.
How much ice at a temperature of -15.7 C must be dropped into the water so that the final temperature of the system will be 33.0 C?
Take the specific heat of liquid water to be 4190 J/kg K, the specific heat of ice to be 2100 J/kg K, and the heat of fusion for water to be 334 kJ/kg.

2007-11-17 08:20:26 · 4 answers · asked by John D 1

A capstan is a rotating drum or cylinder over which a rope or cord slides to provide a great amplification of the rope's tension while keeping both ends free
http://session.masteringphysics.com/problemAsset/1006856/15/36898.jpg
Since the added tension in the rope is due to friction, the capstan generates thermal energy.

A)
If the difference in tension (T_0-T') between the two ends of the rope is 520 N and the capstan has a diameter of 10.0 cm and turns once in 0.90 seconds, find the rate P_thermal at which thermal energy is being generated.
Give a numerical answer, in watts, rounded to the nearest 10 W.

B)
If the capstan is made of iron (with a specific heat capacity C=470 J/(kg C) and has a mass of 6.00 kg, at what rate dTheta/dt does its temperature rise? Assume that the temperature in the capstan is uniform and that all the thermal energy generated flows into it.

Note that Theta is a temperature.
Give answer in degrees Celsius.

2007-11-17 08:18:11 · 3 answers · asked by John D 1

The parachute on a race car that weighs 7250 N opens at the end of a quarter-mile run when the car is traveling 45 m/s. What total retarding force must be supplied by the parachute to stop the car in a distance of 1100 m?
_N

2007-11-17 07:13:03 · 1 answers · asked by Anonymous

Hey Thanks for reading. I am doing my science fair on carnival games. I am expeimenting to see how carnys use science to make the dart and ballon game,tip a troll game and the ball and bucket toss. All I have is my topic, what should i do next?

2007-11-17 07:09:19 · 1 answers · asked by ron 1

Neglect air resistance.

2007-11-17 07:08:16 · 1 answers · asked by Anonymous

a wrench falls from a helicoper that is rising steadily at +6.0m/s. After 2.0 seconds

a. what is the velocity of the wrench
and how far below the heliocper is the wrench?

2007-11-17 07:07:36 · 2 answers · asked by Rachel P 1

A circular disk with mass m and radius R is mounted at its center, about which it can rotate freely. The disk has a moment of inertia I = 1/2 m (R squared) . A light cord wrapped around it supports weight mg. Find the total kinetic energy of the system when the weight is moving at a speed v.

2007-11-17 06:56:31 · 2 answers · asked by Anonymous

A 15 g bullet traveling horizontally at 865 m/s passes through a tank containing 13.5 kg of water and emerges with a speed of 534 m/s. What is the maximum temperature increase that the water could have as a result of this event?

All that I could think of is using the Quantity of heat equation of course ( Q=mc(change in)T). I have no idea what temperatures to start out with and how to use the velocity. Thanks for any inputs!

2007-11-17 06:37:26 · 3 answers · asked by Neil L 1

removed to cool and freeze the water at 0 degrees C?

2007-11-17 06:34:25 · 2 answers · asked by Anonymous

Like in that Superman film?

2007-11-17 06:17:55 · 40 answers · asked by The Doctor 4

There is a 2 kg block being pushed up a vertical wall at a constant velocity for a dist of 3 m and the coeff. of friction is .30. A constant force is applied at an angle of 28 deg with the horizontal. Find the magnitude of normal force btw the block and the wall.
Now I found the horizontal component to be 17.32 but I can't find the vertical component. I've done everything possible but can't solve this.

2007-11-17 06:11:08 · 5 answers · asked by Crashovdr 4

Given two amsses, 3m and 4m, where the 3m mass is moving with a velocity v1 colliding with the 4m mass, which is suspended by a string of length L. The two masses are stuck together as the result of the collision. The compound system swings to the right and stops at the horizontal level. Find the kinetic energy K of the compound (theoretically).

2007-11-17 06:01:24 · 2 answers · asked by Anonymous

2007-11-17 05:37:41 · 4 answers · asked by Sweetness 1

2007-11-17 05:36:40 · 1 answers · asked by Sweetness 1

2007-11-17 04:43:45 · 2 answers · asked by Selim K 1

A space shuttle has a mass of 2.5 x 10^6 kg. At lift-off the engines generate an upward force of 30 x 10^6 N. What's the weight of the shuttle in newtons? What's the acceleration of the shuttle when launched in m/s^2? The average acceleration of the shuttle during its 10 minute launch is 14 m/s2. What velocity does it attain in km/s?

2007-11-17 04:43:26 · 2 answers · asked by Anonymous

Equipment to be used in airplanes or spacecraft is often subjected to a shake test to be sure it can withstand the vibrations that may be encountered during flight. A radio receiver of mass 5.25 kg is set on a platform that vibrates in SHM at 116 Hz and with a maximum acceleration of 93 m/s2 (= 9.5 g).
(a) Find the radio's maximum displacement.
m
(b) Find the radio's maximum speed.
m/s
(c) Find the maximum net force exerted on it.
488.25 N

I found answer c but i do not know how to find a or b and have been trying to solve it for hours now.

2007-11-17 04:38:50 · 1 answers · asked by Anonymous

NOTE: They have equal kinetic energies!!!

2007-11-17 04:38:47 · 3 answers · asked by Selim K 1

If you never heard of Newman, please do a search of him.
Over 40 scientist has signed affidavits stating the possibility of this new technology. Do you believe the reason this new technology has not come about because of national security concerns?
This is my reply to dansinge from the last time I posed this question: The problem with many academia physics is they haven't had an original thought in their life. So please don't mimic the First Law of thermodynamics to me. In addition, it would nice if so-called physicist on this site explain how forty scientist supposedly got dupe by Joseph Newman. Please don't give lame explanations for t

2007-11-17 04:31:41 · 1 answers · asked by Anonymous

It has to travel at least 1.5 meters.

2007-11-17 04:14:15 · 3 answers · asked by Jill 2

2007-11-17 03:51:53 · 7 answers · asked by lilliam r 1