Physics - November 2007

A cannonball launched with an initial velocity of 146 m/s at and angle of 30° follows a parabolic path and hits a balloon at the top of its trajectory. Neglecting air resistance, how fast is it going when it hits the balloon?

What is the acceleration of the cannonball just before it hits the balloon?

2007-11-25 06:42:17 · 2 answers · asked by Anonymous

Assume that at the top of a pole vault, the athlete's speed is zero. The safety mat is 0.40m thick!

Apply the law of conservation of energy to determine the maximum speed with which the athlete lands after clearing the crossbar set at 4.6m

I realize that it might be a bit difficult because this will require both physics and sports knowledge, none of which I acquire

2007-11-25 06:35:05 · 2 answers · asked by Anonymous

What is the formula for net work?

The formula for potential energy change?

An Amount of work equal to 1.5J is required to compress the spring in a spring-gun. what is the launch speed of a 15-g marble?

2007-11-25 06:29:39 · 1 answers · asked by Afolly babe 1

Given: density of water = 1000 kg/m^3 and
specific heat of water = 4186 J/kg * degrees Celsius
In a showdown on the streets of Laredo,
the good guy drops a 15.8 g silver bullet, at
a temperature of 44 degrees C, into a 31 cm^3 cup
of water at 41 degrees C. Simultaneously, the bad
guy drops a 15.8 g copper bullet, at the same
initial temperature, into an identical cup of
water.
What is the coolest final temperature? (In
other words, which one ends the showdown
with the coolest cup of water in the West)?
Neglect any energy transfer into or away from
the container and assume the specific heat
of silver and copper are 234 J/kg * degrees C and
387 J/kg * degrees C (respectively). Answer in units of degrees C. Your
answer must be within 0.01% of the correct answer

2007-11-25 06:27:59 · 1 answers · asked by Handiman 3

Given a two-mass pendulum, that is, two masses attached to a rod (of negligible mass) with the pivot point at the middle of the rod, what is the period of the pendulum when released from rest (with the rod horizontal) if one mass is 200 g, the other is 100 g, and the length of the rod from the midpoint to each mass is 20 cm (the rod is 40 cm long in all)?

2007-11-25 06:13:50 · 2 answers · asked by Anonymous

2007-11-25 05:55:07 · 9 answers · asked by Anonymous

please I need an explanation of what it means when we say that cirrent (I) is proportional to voltage (V)...
Thanks

2007-11-25 05:52:30 · 3 answers · asked by mibg 1

A 0.20 kg baseball moving at +20.60 m/s is slowed to a stop by a catcher who exerts a constant force of -351 N.
How long does it take this force to stop the ball?
How far does the ball travel before stopping?

2007-11-25 05:49:07 · 1 answers · asked by andyjumpman23 3

a tightrope walker weighing 145 pounds is standing still at the center of a tightrope that is 46.5 feet long. the weight of the walker causes the center of the tightrope to move down 14.5 inches. find the magnitude of the tension in the tightrope .

2007-11-25 05:49:03 · 1 answers · asked by Anonymous

A 2220 kg car traveling at 11.9 m/s collides with a 2670 kg car that is initially at rest at the stoplight. The cars stick together and move 2.40 m before friction causes them to stop. Determine the coefficient of kinetic friction between the cars and the road, assuming that the negative acceleration is constant and that all wheels on both cars lock at the time of impact.

2007-11-25 05:47:50 · 1 answers · asked by andyjumpman23 3

We have a wire of 1 m and we bend it in a shape of S. When I say "in shape of S" I mean by sides being verticals and horizontals not curvey sides.

Okay so Four sides of the shape of S are 22.22 cm and one side is 11.11 cm, making it 1 m. So how do I find the center of mass:

1) by hanging the configuration, S, from a string or hook.
2) by measuring the configuration, S, and calculating the Center of mass with formulas.

And one more thing the sides could be on any side it doesnt matter.

Thanks in advance

2007-11-25 05:45:08 · 2 answers · asked by Anonymous

sufficient speed to pass directly into the tissue beneath the skin. The speed is high, because the vaccine (1100 kg/m^3) is held in a reservoir where a high pressure pushes it out. The pressure on the surface of the vaccine in one gun is 4.18*10^6 pa above the atmospheric pressure outside the narrow opening. The dosage is small enough that the vaccine's surface in the reservoir is nearly stationary during an inoculation. The vertical height between the vaccine's surface in the reservoir and the opening can be ignored. Find the speed at which the vaccine emerges.

Please Help!

2007-11-25 05:23:37 · 1 answers · asked by iqbalkhanayesha 2

For example, if speed of sound was 332m/s would the particles of air necessarily move at this speed.. why or why not?

2007-11-25 05:16:40 · 1 answers · asked by Anonymous

Tarzan swings on a 24.0 m long vine initially inclined at an angle of 35° from the vertical.

(a) What is his speed at the bottom of the swing if he starts from rest?

(b) What is his speed at the bottom of the swing if he starts with an initial speed of 2.78 m/s?

2007-11-25 05:16:28 · 3 answers · asked by Anonymous

A bit of space debris penetrates the hull of a spaceship traversing the asteroid belt and comes to rest in a container of water that was at 0oC before being hit. The mass of the space rock is 0.92g and the mass of the water is 1.15kg. If the space rock traveled at 8.17 x 103 m/s, and all of its kinetic energy was used to heat the water, what is the final temprature of the water?
Assume the interaction happens fast enough that the water does not boil.

2007-11-25 05:11:37 · 1 answers · asked by Anonymous

a horizontal force of 198 N is exerted on a 20 kg wooden box in order to slide it up a 30 degree incline. the coefficient of kinetic friction is 0.2. Find the force of kinetic friction. Find the acceleration of the system.

2007-11-25 05:09:48 · 1 answers · asked by Anonymous

A city planner is working on the redesign of a hilly portion of a city. An important consideration is how steep the roads can be so that even low-powered cars can get up the hills without slowing down. It is given that a particular small car, with a mass of 1050 kg, can accelerate on a level road from rest to 22 m/s (79.2 km/h) in 14.0 s. Using this data, calculate the maximum steepness of a hill.

2007-11-25 04:52:28 · 2 answers · asked by se.berk 1

Just wondering

2007-11-25 04:44:55 · 27 answers · asked by Dicky 1

can some1 describe the functioning of amplifiers briefly? what are the differences b/w an inverting & non-inverting amplifier besides dat of input aplied on diferent terminals?
what is open loop gain?
plzzz help...i need all this info badly.

2007-11-25 04:41:50 · 3 answers · asked by pearl 1

A magician attempts to catch a bullet with his teeth. The mass of the bullet is 15 grams and its initial speed is 200 m/s as it leaves the gun.

1. Calculate the final speed of the combined mass of his skull (6 kg) and the bullet, assuming that his head starts from rest.

2. If his head acquires this new speed in a movement of 5 cm, calculate the acceleration that his head must undergo in g's.

My answers:

1. .499 m/s

2. Acceleration comes out to (-2.49 m/s^2) which is equal to .2541 g's.

Am I right? Thanks.

2007-11-25 04:32:29 · 1 answers · asked by labelapark 6

A 2.30 x 10^2-N force is pulling an 85.0-kg refrigerator across a horizontal surface. The force acts at an angle of 24.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 5.00 m. Find: (a) the work done by the pulling force, and
(b) the work done by the kinetic frictional force.

2007-11-25 04:29:39 · 1 answers · asked by Anonymous

What is the magnitude of this acceleration in km/seconds squared?.

Thanks. any help is appreciatied.

2007-11-25 04:28:38 · 1 answers · asked by ... :) 2

In science fiction films they use a laser beam coming from a laser gun as a special effect. Why would we not see a beam coming from the laser gun?

2007-11-25 04:10:39 · 4 answers · asked by Anonymous

What happens if we built a a road that went all around the world with nothing holding it up, the gravity would surley pull it down, but tht would mean the other side of the worlds road, would go in the air, but then gravity would pull it, so what happens? does it float?

2007-11-25 03:48:08 · 3 answers · asked by Anonymous

2007-11-25 03:38:08 · 4 answers · asked by Mo 2

The normal force ( directed downwards ) provided by the track at the top of the loop is equal to one-half the weight of the car.
What is the speed of the coaster at this point ?

2007-11-25 03:33:34 · 4 answers · asked by Anonymous

In a circus act, a 60 kg trapeze artist starts from rest with the 5 m trapeze rope horizontal. What is the tension in the rope when it is vertical?

Please help! I have tried a bunch of things but I can't get the right answer!

2007-11-25 03:25:21 · 7 answers · asked by Anonymous

I have been given this weekend physics task of finding out what happens at certain temperatures (We are in the topic of matter and e=kt and all that stuff...) The book I have gives examples such as:

At 6 million K, ionisation of inner electrons of atoms...

Apparently, according to my physics teacher, thats boring...

Anyone have any ideas of any interesting temperature stuff?

2007-11-25 03:24:38 · 4 answers · asked by Sean 3

Need to find v.w describe answer in practical term.

2007-11-25 02:57:19 · 4 answers · asked by danahen2000 1

It's about glasses for color deficients. This kind of glasses change the spectrum of light which is passing through it. I want to know if the same think happens to the prism http://en.wikipedia.org/wiki/Image:Prisma.gif Pleeeease heeelp, i need this for a project.

Thank you.

2007-11-25 02:50:41 · 1 answers · asked by Gabriela I 1