Physics - October 2007

The vertical rods each have mass of 14 g; the horizontal rod has mass of 48 g.
Where is the center of mass of the assembly?
(x, y) = ( , ) cm

2007-10-25 06:56:03 · 2 answers · asked by Wonder 2

A 34.0 kg seal at an amusement park slides down a ramp into the pool below. The top of the ramp is 1.55 m higher than the surface of the water and the ramp is inclined at an angle of 30.0° above the horizontal. The seal reaches the water with a speed of 4.90 m/s.

(a) What is the work is done by kinetic friction?

(b) What is the coefficient of kinetic friction between the seal and the ramp?

Neither my friend nor I can figure this one out. Any help will be very much appreciated. Thanks!!!

2007-10-25 06:41:05 · 4 answers · asked by Imagine 1

2007-10-25 06:30:40 · 8 answers · asked by mortimer 2

2007-10-25 06:23:01 · 1 answers · asked by Anonymous

can any one please describe buoyancy for me in terms of pressure, depth, force and density and so on... thanks!

2007-10-25 05:56:05 · 2 answers · asked by john l 1

2007-10-25 05:49:06 · 3 answers · asked by Shivam 1

There are two fields- magnetic and electric which are parallel to each other. If a particle is placed on the magnetc field, what would be the direction of this particle.(how would it move)

2007-10-25 05:43:40 · 1 answers · asked by meeta1704 2

Well, had a debate about gravity, and was wondering, does gravity pull down, or does it pull in, towards the Earth's core? Are down and in the same thing, or are they differant? If they are differant, how so? Please provide any examples and referances for this question.

2007-10-25 05:30:19 · 5 answers · asked by Obsidian 2

A 34.0 kg seal at an amusement park slides down a ramp into the pool below. The top of the ramp is 1.55 m higher than the surface of the water and the ramp is inclined at an angle of 30.0° above the horizontal. The seal reaches the water with a speed of 4.90 m/s.
(a) What is the work is done by kinetic friction?
(b) What is the coefficient of kinetic friction between the seal and the ramp?

I am having some trouble with this one. Any help would be much appreciated. Thanks!

2007-10-25 05:04:48 · 4 answers · asked by Tana 1

A 2.8 kg block slides with a speed of 1.1 m/s on a frictionless, horizontal surface until it encounters a spring.

(A) If the block compresses the spring 5.7 cm before coming to rest, what is the force constant of the spring?

(B) Find the greatest height of the rock as measured from the base of the cliff.

Ok, I feel rather dumb for not being able to get this, but I get the wrong answer every time. Help please!

2007-10-25 05:02:39 · 2 answers · asked by Anonymous

A carnival game requires you to knock over a wood post by throwing a
ball at it. You're offered a very bouncy rubber ball and a very sticky
clay ball of equal mass. Assume that you can throw them with equal
speed
and equal accuracy. You only get one throw.

Which ball will you choose? Why?

2007-10-25 04:54:26 · 2 answers · asked by You Know Who 2

Is it ok if I park a 40 ton truck on your foot ?

2007-10-25 04:26:34 · 5 answers · asked by John S2005 3

2007-10-25 04:22:18 · 2 answers · asked by superdruft186 1

If i launch 3 bottle rockets of varying weight, will the one with the most weight have a longer travel time? OR will the one with the least weight have more travel time?

2007-10-25 04:21:11 · 5 answers · asked by Heather 3

2007-10-25 04:03:17 · 2 answers · asked by kleenexpocketpack 1

In a tennis match, a player wins a point by hitting the ball sharply to the ground on the opponent's side of the net.

If the ball bounces upward from the ground with a speed of 18 m/s and is caught by a fan in the stands with a speed of 12 m/s, how high above the court is the fan? Ignore air resistance.

Help please. I just can't figure this one out.

2007-10-25 03:56:00 · 4 answers · asked by Imagine 1

A. electrons
B. protons
C. neutrons
D. nothing

2007-10-25 03:28:33 · 6 answers · asked by Broken Blue Eyes 6

A cart with mass 200. g has a velocity of 0.30 m/s in the positive x direction. What is the momentum of the cart?
This cart collides with a stationary cart of mass 400 g.
If the velocity of the first cart is -0.1000 m/s after the collision, what is the velocity of the second cart after the collision?What type of collision is this?

2007-10-25 03:21:10 · 2 answers · asked by Natiphy2007 1

We know our three existing dimensions are length, width and height... but what would the fourth dimension be? Time?

How can we comprehend other dimensions beyond that?

2007-10-25 03:15:30 · 5 answers · asked by Anonymous

There would be a small heater and blower motor installed in your plenum. The heater,a 150 watt light bulb, would draw 150 watts. The blower motor would draw 176 watts.

I am thinking of experimenting with this heater in my 1000 square foot home. The proposed system would utilize the ducting installed in my home for the oil fired hot air furnace. Inside the hot air plenum would be placed two incandescent flood lamps, each maybe 150 watt bulbs. The heater wattages could be increased to two 150 watt bulbs as necessary to keep up with demand for heat. Also there would be a small 176 watt blower motor, the kind you use in an air purifier unit. The idea is to produce just enough air flow and heat so that this furnace runs continuously to keep up with demand for heat, so as to avoid start up currents and start stop wear and tear on parts.

My calculations, and I would like for you to check them if possible, show that I would be consuming 326 watts per hour or .326kwh. If the system was running continuously for 24 hours a day(7.824KWH per day), 30 days a month(234.72KWH per month), @.09 per KWH it would cost .09 x 234.72KWH or $21.12 per month. How is that for a heating bill?

I am unsure as to whether running continuously it will keep up with the heat demand for a 68 degree temperature in my home? Any experts out there? Anything like this on the market now for furnaces?

2007-10-25 03:07:57 · 1 answers · asked by Anonymous

An FM station broadcasts classical music at 89.5 MHz (megahertz, or 106 Hz). Find the wavelength (in m, nm, and ) of these radio waves.

2007-10-25 01:40:50 · 12 answers · asked by Anonymous

2007-10-25 01:28:30 · 13 answers · asked by Jk 1

A solid ball of mass 15 kg is at the top of a frictionless incline 2 m high and 10 m long. If it rolls down the incline, find its:

(a) initial potential energy
(b) final kinetic energy
(c) final velocity.

So far, I've done (a), hopefully it's right.

I did ...

GPE = mgh, so 15 x 9.8 x 2 = 294 J.

I'm stuck with the next part, (b).

The formule is KE = mv2 (squared) divided by 2.

I've got the mass but the thing is I don't have the velocity to work out the kinetic energy.

To work out the velocity you generally need the kinetic energy.

I'm confused.

If anyone could help out that'd be great.

This is tenth grade physics by the way =)

2007-10-25 00:41:18 · 5 answers · asked by Your Mother. 2

2007-10-25 00:06:38 · 6 answers · asked by Itchy1977 4

All I know is that it is "annihilated".

2007-10-24 23:57:39 · 8 answers · asked by honourableone 3

I conducted an experiment, investigating how density affect a projectile with the presence of air resistance. (The object is launched horizontally from a height of 92cm)

Before the experiment, I researched and asked opinions from other people, all of which gave the same view---> greater density=greater distance. And this was the base of my hypothesis....

But the experiment turned out to be the exact opposite of my hypothesis. My results indicate that less density=higher distance. My average results are as follows:
(Objects have the same shape - 60cm^3 block)

1)Wood (density=0.467) - distance = 190cm
2)Wax (0.917) - 125cm
3)Aluminium (2.683) - 58cm
4)Iron (7.817) - 25cm

WHY is it like this? What's wrong? What seems to be the problem?

PLEASE help if you can... and try and explain cearly (my knowledge in physics is only sixth form level)

OH please i beg for your help and opinion..I'm mentally blocked right now, out of ideas... AND in need of some HELP

2007-10-24 22:40:10 · 8 answers · asked by max88 2

I thought that when things bounced off other things they imparted more momentum (twice) then if they are just absorbed. since heating things is like imparting momentum to the molecules that make up the substance, and light does exert pressure, why is it that things that absorb light tend to heat up more than things that reflect it?

2007-10-24 22:24:29 · 5 answers · asked by keyahnoo 2

Physics question. Here is scenario: 2 syringes filled with air; one a 10cc, the other a 30cc; plunger surface areas about 0.22 and 0.44sq inches respectively; syringes held back to back with plungers touching each other; I force the 10cc syringe against the 30cc syringe and measure STATIC pressures at the exit ports using digital manometers. Pressures are different. Why does Pasqal's law not apply? Example: 10cc syringe reads 20psi when the 30cc syring reading 20psi (air in 10cc syring appears considerably more compressed).

2007-10-24 22:00:06 · 2 answers · asked by Dr. Sully 1

An boy throws a stone of mass 1kg. The stone is released with an initial velocity 5m/s
at an angle 30o above horizontal while it is at the height 1.28m. How far from the boy
will the stone land? What is the speed of the stone when it hits the ground? What is
the highest altitude the stone reaches?

2007-10-24 20:22:22 · 3 answers · asked by Dragon 1

a) on B from A?
b) on A from B?

2007-10-24 19:36:44 · 3 answers · asked by =P 6