Physics - October 2007

A physics student playing with an air hockey table (a frictionless surface) finds that if she gives the puck a velocity of 3.80 m/s along the length(1.75 m) of the table at one end, the puck has drifted 2.50 cm to the right but still has a velocity component along the length of 3.80m/s. She correctly concludes that the table is not level and correctly calculates its inclination from the above information. What is the angle of inclination?

2007-10-18 08:46:08 · 2 answers · asked by selece_wingard 1

I will appreciate your help, and I ned someone to explain me how can I attached some graphs to this questions.
Question 1)
a) What is the constant of the spring?
b) From your graph (force vs. distance), does the spring follow Hooke’s law?
c) Do you think that it would always follow Hooke’s law no matter how far you stretched it?
d) Why is the slope of your graph positive, while Hooke’s law has a minus sign?
Question 2)
Compare the work you measured to stretch the spring to 10 cm, 20 cm, and the maximum stretch to the stored potential energy predicted by this experiment. Should they be similar?
Stretch
10 cm 20 cm Max. Stretch
Integral (during pull) (N∙m) 0.0865 0.25 0.752
∆ PE (J)

2007-10-18 08:31:49 · 2 answers · asked by Natiphy2007 1

A 5.0 kg block is pushed 4.0 m up a vertical wall with constant speed by a constant force of magnitude F applied at an angle of = 30° with the horizontal, as shown in Figure P5.70. If the coefficient of kinetic friction between block and wall is 0.30, determine the work done by each of the following.


(a) the force
J
(b) gravity
J
(c) the normal force between block and wall
J
(d) By how much does the gravitational potential energy increase during the block's motion?
J

2007-10-18 08:06:14 · 3 answers · asked by Anonymous

The m1 = 5.35 kg object is released from rest at a point 4.00 m above the floor, where the m2 = 3.30 kg object rests.


(a) Determine the speed of each object when the two pass each other.
m/s
(b) Determine the speed of each object at the moment the 5.35 kg mass hits the floor.
m/s
(c) How much higher does the 3.30 kg mass travel after the 5.35 kg mass hits the floor?
m

2007-10-18 08:03:55 · 2 answers · asked by Anonymous

According to Dalton's atomic theory, an atom is:
a) made of smaller particles
b) a particle with a positive charge
c) the smallest particle of an element
d) in constant motion
e) a particle with a negative charge

2007-10-18 07:52:22 · 1 answers · asked by Anonymous

(a) Always lies at the center of the object,
(b) Is at the location of the most massive particle in the object,
(c) Always lies within the object,
(d) None of the above?

2007-10-18 07:43:48 · 5 answers · asked by Pascal 4

a) have no energy
b)have the lowest possible energy
c) have the highest possible energy
d) are in an excited state
e) are in an unstable state

2007-10-18 07:43:01 · 5 answers · asked by Anonymous

2007-10-18 07:41:12 · 1 answers · asked by Pascal 4

A 50000kg ship sails east at 6m/s for 10 minutes. What is the net force acting on the ship? I thought this was so easy but I got it wrong...I had (50000kg*.01m/s^2)...is this because there is no acceleration?

2007-10-18 07:27:58 · 3 answers · asked by Erika H 5

Parallel axis theorem is I = Io + Md^2

So say I have two spheres, equal weight and size, and I have a massless rod to hang them on. In one case I put the spheres on opposite ends and rotate about the middle of the rod -- it's really easy. In the second case I put both spheres on one end and try to rotate about the same point on the rod, it's much harder. This makes sense intuitively...

However, with a d-squared term, the moment of inertia shouldn't depend on where I put the spheres:
Case 1: I-total = Isphere + M(-D)^2 + Isphere + M(D)^2
Case 2: I-total = 2 * ( Isphere + M*(D)^2 ), which is the same.

But why, if the MOI is the same for both cases, is the balanced rod much easier to rotate?

It makes sense in my head, but not mathematically...

Thanks!

2007-10-18 07:25:59 · 1 answers · asked by Michael 4

The desperate contestants on a TV survival show are very hungry. The only food they can see is some fruit hanging on a branch high in a tree. Fortunately, they have a spring they can use to launch a rock. The spring constant is 1400 N/m, and they can compress the spring a maximum of 10.0 cm. All the rocks on the island seem to have a mass of 330 g.

2007-10-18 06:56:46 · 2 answers · asked by rochesmk 2

box and floor are = 0.190 and = 0.150. The truck stops at a stop sign and then starts to move with an acceleration of 2.22

If the box is a distance 1.79 from the rear of the truck when the truck starts, how much time elapses before the box falls off the truck?
Take the free fall acceleration to be = 9.80
In seconds
How far does the truck travel in this time?
Take the free fall acceleration to be = 9.80 .
In meters

2007-10-18 06:51:46 · 2 answers · asked by Bugz 3

A 81.5 kg man is riding an escalator in a shopping mall. The escalator moves the man at a constant velocity from the ground level to the floor above, a vertical height of 5.45 m. What is the work done on the man by each of the following forces?
(a) the gravitational force
___J
(b) the escalator
___ J

2007-10-18 06:39:09 · 5 answers · asked by Santina E 1

A projectile of mass 2 kg approaches a stationary target body at 4.9 m/s. The projectile is deflected through an angle of 59.5° and its speed after the collision is 2.8 m/s. What is the magnitude of the momentum of the target body after the collision?

2007-10-18 06:35:35 · 1 answers · asked by angie 1

A 2 kg mass is attached to a string which is attached to a second mass 1 kg The string passes over a pulley and the two masses both hang down. They are released from rest. How long does it take for each to move 0.9 metres?

A. 0.52 s
B. 1.35 s
C. 0.74 s
D. 0.25 s
E. 0.17 s

2007-10-18 05:06:13 · 1 answers · asked by Bryan K 1

Q:1-A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 kmph passes directly overhead an anti aircraft gun.At what angle from vertical should the gun be fired for the shell with muzzle speed 600m/s to hit the plane? At what minimum altitude should the pilot fly to avoid being hit?

Q:2-Obtain an expression for work done in moving a body up an inclined plane if the coefficient of friction between the body and the plane is u (meu).

no weird ans plz.
i will b very thankful 2 d person who gives me d answers!!!

2007-10-18 04:59:08 · 3 answers · asked by Anonymous

A new record for running the stairs of the Empire State Building was set on February 3, 2003. The 86 flights, with a total of 1576 steps, was run in 9 minutes and 33 seconds. Consider a scenario where a man ran up 1600 steps of the Empire State Building in 10 minutes and 59 seconds. If the height gain of each step was 0.20 m, and the man's mass was 61.0 kg, what was his average power output during the climb? Give your answer in both watts and horsepower.

Help if you can please.

2007-10-18 04:49:11 · 3 answers · asked by Imagine 1

A net force changes the velocity of a 10 kg object by 1m/s every second. How long will it take this net force to change the velocity of a 100 kg object by 1 m/s?

2007-10-18 04:46:13 · 1 answers · asked by chiropteran 1

An astrophysicist working at an observatory is interested in finding clouds of hydrogen in the galaxy. Usually hydrogen is detected by looking for the Balmer series of spectral lines in the visible spectrum. Unfortunately, the instrument that detects hydrogen emission spectra at this particular observatory is not working very well and only detects spectra in the infrared region of electromagnetic radiation. Therefore the astrophysicist decides to check for hydrogen by looking at the Paschen series, which produces spectral lines in the infrared part of the spectrum. The Paschen series describes the wavelengths of light emitted by the decay of electrons from higher orbits to the n=3 level.

2007-10-18 04:45:26 · 2 answers · asked by Anonymous

2007-10-18 04:41:56 · 3 answers · asked by Anonymous

At what minimum speed must a roller coaster be traveling when upside down at the top of a circle if the passengers are not to fall out. The radius of curvature is 7.54 metres. The mass of the passenger is 72.00 kg. [Answer in km/h]

A. 8.6 km/h
B. 30.9 km/h
C. 16.3 km/h
D. 13.3 km/h
E. 74.9 km/h

2007-10-18 04:40:50 · 4 answers · asked by Anonymous

Any formula that you can use to prove your answer?

2007-10-18 04:40:12 · 1 answers · asked by charm 1

A 2 kg mass is attached to a string which is attached to a second mass 1 kg The string passes over a pulley and the two masses both hang down. They are released from rest. How long does it take for each to move 0.9 metres?
A. 0.52 s
B. 1.35 s
C. 0.74 s
D. 0.25 s
E. 0.17 s

2007-10-18 04:39:24 · 2 answers · asked by Anonymous

What is an electromagnetic wave? Name four types of electromagnetic radiation other than visible light

2007-10-18 04:29:57 · 4 answers · asked by Anonymous

A particular race car can cover a quarter mile in 6.8 seconds, starting from a standstill. If acceleration is constant how many g's does the driver experience? If the combinded mass of the driver and race car is 455 kg what is the horizontal force exerted on the tires? in N

2007-10-18 04:13:24 · 2 answers · asked by matt c 1

The problem I'm working on states:
Objects with masses of 120 kg (m1) and a 420 kg (m2) are separated by 0.310 m (m3).
(a) Find the net gravitational force exerted by these objects on a 50.0 kg object placed midway between them.
[The answer I found is 4.1642E-5]
(b) At what position (other than infinitely remote ones) can the 50.0 kg object be placed so as to experience a net force of zero?
___ m from the 420 kg mass

To solve B, would I set the net gravitational force equal to zero? ((Gm1m3)/r^2) + ((Gm2m3)/r^2) = 0, and solve for r?

2007-10-18 04:12:09 · 2 answers · asked by Bill 1

in detail please........

2007-10-18 03:18:55 · 10 answers · asked by possimpible 2

1. Why are these forces often called fundamental or basic forces?
2. Where are these forces found?
3. How are other forces related to them?

2007-10-18 01:58:50 · 2 answers · asked by Cristina V 2

I'm doing a lot of stuff on magnets at school this term and Im curious about electromagnets. I know how to make a basic one but im wondering about how you could make them even stronger. Like if you wrapped wiring around a large piece of iron and hooked the wiring up to a car battery how powerful would that be?
I need to get a better idea about how they work - like industrial magnets.
(And no I dont intend to make them myself because Im too keen on living)

2007-10-18 00:31:30 · 4 answers · asked by George W 1

And where did all this space come from? lol

How would you explain everything?

2007-10-18 00:18:12 · 4 answers · asked by Cally 3