Physics - December 2007

A man in an elevator goes down at a fixed speed.
Does his mass's wheight increase, or decrease compared to when he stands still on the ground?

2007-12-14 07:17:46 · 4 answers · asked by ProDigit 3

If I were to toss a tennis ball straight up in the air on a fast moving subway car, why does it come right down to me and not fall to the back of the train? Is it that there is already forward momentum from the toss?

2007-12-14 05:39:55 · 10 answers · asked by Swede 2

2007-12-14 05:19:09 · 16 answers · asked by Satchelle J 1

There are many theories in the field of physics that are unexplained. One such theory is the multiverse theory, which may be proven sometime next year. If there are truly 11 dimensions and we may live in one of countless universes, then could there be an unexplained supernatural dimension? For example, if there were a supernatural dimension, could this explain God? I am not referring to any specific god, but just a generalization.

2007-12-14 05:17:59 · 10 answers · asked by Anonymous

His wife used to help with all the math,besides that he never really
did anything great after his divorce.

2007-12-14 05:13:44 · 18 answers · asked by Anonymous

2007-12-14 05:13:34 · 6 answers · asked by Anonymous

2007-12-14 04:55:52 · 8 answers · asked by doug 1

i'm looking for the answer to 'what will happen when all the coal runs out? is coal renewable?' because i'm look in for the answer for my yr 7 science fuel work and i'm trying to find out wich is best!

p.s i'm not looking on here for a cheat!

2007-12-14 04:30:36 · 9 answers · asked by c_rick2003 1

without drag or friction. How high will the car coast up the next hill?

2007-12-14 04:12:50 · 3 answers · asked by Anonymous

I know that wieght = mass * gravity , but I don't think that is what is going on here.

Is it that we are using the pound-mass (lbm), when we say pound?

What is going on, I've always been confused about our system?

2007-12-14 04:03:55 · 5 answers · asked by KEYNARDO 5

See The cat's question:

http://answers.yahoo.com/question/index;_ylt=ApZo01JFGON920IYeGRPJUHsy6IX;_ylv=3?qid=20071213163311AAyMl2Z&show=7#profile-info-AA12298210

Assuming that Earth is 8,000 miles in diameter and rotates 24 hours a day, and disregarding gravity, if Bart skates frictionlessly from the north pole to the equation via a straight tunnel, how fast will he be going by the time he exits the tunnel? Acceleration will be due to centrifugal force of the spinning Earth, and you may simplify the problem by also disregarding coriolis forces outside of the plane of the tunnel and center of the earth.

2007-12-14 04:03:37 · 3 answers · asked by Scythian1950 7

A 2 kg cube of iron at 300 C is placed on a 5 kg block of ice at 0 C. How much ice will change to liquid water at 0 C the specific heat of iron is 450 and the heat of fusion of ice is 3.34x10^5

2007-12-14 03:30:41 · 1 answers · asked by Katie E 2

Volcanoes on the Earth eject rocks at speeds of up to 110 m/s. Consider a 1000 m high volcano which ejects rocks in all directions. What is the maximum height above sea level reached by rocks?




What is the maximum horizontal distance at sea level reached by the rocks?

2007-12-14 03:09:54 · 3 answers · asked by Monty 1

A projectile is fired at 45.0° above the horizontal. Its initial speed is equal to 127.5 m/s. Assume that the free-fall acceleration is constant throughout and that the effects of the air can be ignored. What is the maximum height reached by the projectile?


At what time after being fired does the projectile reach this maximum height?

2007-12-14 03:02:28 · 3 answers · asked by Monty 1

And, since that's the theory which explains parallel universes so well...does e=Mc2 now mean...energy = membranes x the speed of Light squared?

2007-12-14 03:00:03 · 8 answers · asked by Elysabeth 7

In her physics lab, Jessica rolls a 17-g marble down a ramp and off the table with a horizontal velocity of 1.04 m/s. The marble falls in a cup placed 0.52 m from the table's edge. Find the table's height. Use g = 10. m/s2. Enter m as unit

2007-12-14 02:56:13 · 2 answers · asked by Monty 1

At O degrees celcius a cannon fires a shell at 1324m/s.

a) how fast is the shell travelling relative to the sound wave from the explosion?
*b) how far away from the cannon is an observer who sees the shell pass by 2.00s before the sound of the explosion arrives?

2007-12-14 02:53:21 · 3 answers · asked by Anonymous

A person's body is producing energy internally due to metabolic processes. If the body loses more energy than metabolic processes are generating, its temperature will drop. If the drop is severe, it can be life-threatening. Suppose a person is unclothed and energy is being lost via radiation from a body surface area of 1.38 m2, which has a temperature of 34°C and an emissivity of 0.700. Suppose that metabolic processes are producing energy at a rate of 103 J/s. What is the temperature of the coldest room in which this person could stand and not experience a drop in body temperature?

2007-12-14 02:44:03 · 1 answers · asked by ncote119 1

-a ball rolling up on a inclined plane.
-a car ascends a steep hill.
-a girl jumps down from a bed
-water is forced upward through a pipe.
-a crate rests at the bottom of an inclined plane.

2007-12-14 02:42:21 · 2 answers · asked by fivefootzero 2

What is the kinetic energy of an automobile with a mass of 1040 kg traveling at a speed of 13.4 m/s?

and

What speed would a fly with a mass of 0.65 g need in order to have the same kinetic energy as a 1250 kg automobile traveling at a speed of 11 m/s?

and

A 65.0 kg diver steps off a diving board and drops straight down into the water. The net force when in the water is an upward 1250 N. If the diver comes to rest 4.0 m below the water's surface, what is the total distance between the diving board and the diver's stopping point underwater?

2007-12-14 01:55:30 · 1 answers · asked by Anonymous

A spring has a force constant of 430.0 N/m.

(a) Determine the potential energy stored in the spring when the spring is stretched 4.16 cm from equilibrium.
J
(b) Determine the potential energy stored in the spring when the spring is stretched 3.32 cm from equilibrium.
J
(c) Determine the potential energy stored in the spring when the spring is unstretched.
J

2007-12-14 01:51:42 · 2 answers · asked by Anonymous

A 2.1 kg ball is attached to a ceiling by a string. The distance from the ceiling to the center of the ball is 0.81 m, and the height of the room is 3.00 m.

(a) What is the gravitational potential energy associated with the ball relative to the ceiling?
J
(b) What is the gravitational potential energy associated with the ball relative to the floor?
J
(c) What is the gravitational potential energy associated with the ball relative to a point at the same elevation as the ball?
J

2007-12-14 01:50:39 · 3 answers · asked by Anonymous

A 64.0 kg diver steps off a diving board and drops straight down into the water. The net force when in the water is an upward 1060 N. If the diver comes to rest 5.9 m below the water's surface, what is the total distance between the diving board and the diver's stopping point underwater?
m

2007-12-14 01:43:05 · 2 answers · asked by Anonymous

Naturaly fall , and how does it opperate in 0 gravity. Do you know how far science has lent study to this matter.

2007-12-14 01:36:59 · 7 answers · asked by G 5

2007-12-14 00:45:16 · 4 answers · asked by Yee Teng L 2

These are the questions that we need to answer in our problem set and case study. Please help!

1. The new EV-1 electric car makes use of storage batteries as its source of energy. Its mass is 1300 kg and it is powered by 26 batteries, each 12 V, 52 A•h. assume that the car is driven on the level at an average speed of 40 km/hr and the average friction force is 240 N. Assume 100% efficiency and neglect energy used for acceleration. Note that no energy is consumed when the vehicle is stopped since the engine doesn’t need to idle. (a) Determine the horsepower required. (b) After approximately how many kilometers must the batteries be recharged?

2. A nerve is stimulated with an electric pulse. The action potential is detected at a point 3.40 cm down the axon 0.0052 s later. When the cation potential is detected 7.20 cm from the point of simulation, the time required is 0.0063 s. What is the speed of the electric pulse along the axon? Why are two measurements needed instead of only on

2007-12-14 00:42:09 · 2 answers · asked by aleic_27 1

minimum frequency for flyback transformer to work?

2007-12-14 00:13:21 · 5 answers · asked by kendrickcbk 2

2007-12-13 23:19:35 · 15 answers · asked by Rock star 2

I got this doubt when i was going through diffrences between pressure and stress.

2007-12-13 22:55:57 · 6 answers · asked by prajwal 1

A mine car, whose mass is 440 kg, rolls at a speed of .5 m/s on a horizontal track. A 150 kg chunk of coal has a speed of .8 m/s when it leaves the chute (sloping downward at 25 degreees above the horizontal). Determine the velocity of the car/coal system after the coal has come to rest in the car.

2007-12-13 22:53:55 · 2 answers · asked by laweezer08 1