Physics - December 2007

the lab says to calculate teh estimated frictional force f using a=(m2-m1)g-f / (m1+m2) then you have to change the problem into f=(m2-m1)g-(m1+m2)a

i dont know how to find the acceleration so that i can solve the problem... can someone help me?

2007-12-16 06:58:36 · 2 answers · asked by zipbang300 1

Is there some type of particles that has a mass lower than the electron?
It will help if you give source of information.

2007-12-16 06:46:20 · 3 answers · asked by Anonymous

The m between rubber tires and wet pavement is 0.50. The brakes are applied to a 1125.15 kg car traveling at 32.60 m/s, and the car skids to a stop. What is the size and direction of the force of friction that causes the car to stop?


then it wants to know what would be the size and direction of the acceleration of the car?

2007-12-16 06:33:01 · 1 answers · asked by molly 1

A roller coaster, (h1 = 30 m, h2 = 15 m, h3 = 25 m), is pulled up to point A where it and its screaming occupants are released from rest. Assuming no friction, calculate the speed at points B, C and D. h1= A is 30m above B. h2= B is 15m below D. h3= B is 25m below C. Help would be greatly appreciated. Thank you. If you have any questions on the view of the diagram please ask.

2007-12-16 05:58:43 · 2 answers · asked by ND03 1

A novice skier, starting from rest, slides down a frictionless 33.0° incline whose vertical height is 120 m. How fast is she going when she reaches the bottom? Help would be greatly appreciated. Thank you.

2007-12-16 05:34:25 · 1 answers · asked by ND03 1

2007-12-16 05:34:19 · 2 answers · asked by Anonymous

Assume: The length of the athletes arm is included in the length given for the chain below.
An athlete whirls an 8.41 kg hammer tied to the end of a 1.3 m chain in a horizontal circle. The hammer moves at the rate of 0.893 rev/sec.
What is the centripetal acceleration of the hammer? answer in units of m/s/s.
What is the tension in the chain? Answer in units of N.

2007-12-16 05:33:47 · 1 answers · asked by Anonymous

on my homework they are asking me :
suppose you are standing in the aisle of a bus traveling along a straight road at 100km/h, and you hold a pencil stil above your head. Then relative to the bus, the velocity of the pencil is 0km/h, and relative to the road, the pencil has a horizontal velocity of :
(less than 100km/hr)
(100km/hr)
or (more than 100km/hr)

HELP!!!
please

2007-12-16 05:30:33 · 1 answers · asked by MiSh3lLi. 1

A 15.6 kg block is dragged over a rough, horizontal surface by a constant force of 77.5N acting at an angle of 27.4 degrees above the horizontal. The block is displaced at 54.2m, and the coefficient of friction is 0.155. The acceleration of gravity = 9.81.

What is the magnitude of the workd done by the force of friction. Answer in joules.

2007-12-16 05:26:24 · 3 answers · asked by alex s 1

1) a string under a tension of 74 N is used to whirl a rock in a horizontal circle of radius 3.4 m at a speed of 26.79 m/s. The string is pulled in and the speed of the rock increases. When the string is 0.627 m long and the speed of the rock is 55.4 m/s, the string breaks.
What is the breaking strength of the string?
Answer in units of N

2) A merry-go-round makes one complete revolution in 16.4 s. A 35.7 kg child sits on the horizontal floor of the merry-go-round 5.52 m from the center
The acceleration of gravity is 9.8 m/s/s
What minimum coefficient of static friction is necessary to keep the child from slipping?

2007-12-16 05:26:04 · 2 answers · asked by Anonymous

How much work is required to pull the skier 60.4 m up a 31.0 degree slope (assumed to be frictionless) at a constant speed of 2.0 m/s? The acceleration of gravity is 9.8 m/s^2. Answer in units of J.

2007-12-16 05:24:24 · 1 answers · asked by Anonymous

degrees above the horizontal. The block is displaced 97.8 m, and the coefficient of kinetic friction is 0.142. The acceleration of gravity is 9.8m/s^2. find the magnitude of the work done by the force of friction. Answer in hte units of J.

2007-12-16 05:19:12 · 2 answers · asked by Anonymous

2007-12-16 05:06:38 · 8 answers · asked by Anonymous

Below. The collision dissipates 50% of the energy as heat. How high does the ball bounce?Answer in meters.

2007-12-16 04:03:31 · 2 answers · asked by mira s 1

I asked how, if matter is neither created nor destroyed, then where did the point the universe expanded from originate, and I got this response:

"*blinks* Honey, how could you go to school and not understand that the law is "ENERGY can be neither created nor destroyed". MATTER is created and destroyed all the time."

Does that make sense at all? As far as I could recall, there was a Law of Conservation of Matter that says that matter is only transformed; never created nor destroyed.

She later sends me this after I gave her an e-mail:

"I never said that matter can't be destroyed idiot. YOU DID. ENERGY cannot be destroyed. Matter turns into energy when IT is destroyed. Because thats what happens to matter, hon. It degrades and is turned into energy and used to fuel OTHER LIFE.

The idiotic thing you just came up with is simply the same as with energy. Since matter is MADE UP OF energy, think about it."

Am I missing something?

2007-12-16 03:39:05 · 10 answers · asked by Stardust 6

A coin of mass .0050 kg is placed on a disk at a distance of .14m from the center. The coin does not stlip and takes 1.5 s to make a complete revolution.

1. What is the linear speed.
2. The rate of the rotation of the disk increases. The coefficient of static friction is .50. Determine the linear speed of the coin just before it slips.

2007-12-16 03:25:23 · 2 answers · asked by Franny 3

this is part of the analysis for the lab
trial 1
radius=.4m
time=10secs
mass=.05kg
rotations=22
How do i calculate linear speed? is it (2*(PI)*r*#of rot) /t?

How do i calculate the centripetal force the object should have had based on the mass, linear velocity, and circle radius? i have no idea how to do this

Ho do i calculate the force needed to keep each mass going in a circle (the weight on the string). Show the calculation of the force for at least one test from each experiment? i have no idea again

2007-12-16 03:25:03 · 1 answers · asked by confused 1

A coin placed 30.0cm from the center ofa rotatating turntable slips when its speed is50.5cm/swhat force causes the centripetal acceleration when the coin is stationary relative to the turntable?what is the coeffecient of static friction

2007-12-16 02:38:17 · 3 answers · asked by Anonymous

I find this to be really difficult problem, and I can't find someone who can answer it.

Two physics students have been selected by NASA to accompany astronauts on a future mission to the Moon. The students are to design and carry out a simple experiment to measure the acceleration due to gravity on the surface of the Moon. Describe an experiment that the students could conduct to measure the acceleration due to gravity on the Moon. The answer must include :
- the equipment needed
- what quantities would be measured using this equipment
- what procedure the students should follow in conducting their experiment
- what equations and/or calculations the students would need to do to arrive at a value for the acceleration due to gravity on the Moon.

2007-12-16 02:36:39 · 7 answers · asked by paliprospect 1

A 18 kg block is in equilibrium on an incline of angle = 45°. Find Fn of the incline on the block.
N

2007-12-16 02:32:34 · 3 answers · asked by NiNi 2

Planet W has a radius of 8.2*10^7m and a gravitational accelaeration of 27m/s^2. Determine the orbital radius of a satellite that orbits this planet in 6.50 days.

2007-12-16 02:25:13 · 1 answers · asked by Franny 3

Two students are in the library sitting across the table from each other. One student takes a book with a mass of 1.65 kg and pushes it across the table with a net force of 6 N. What is the acceleration of the book?

2007-12-16 02:08:04 · 2 answers · asked by molly 1

a planet has a mass of 6.2*10^25 kg and a radius of 2.42*10^6m. Determine the gravitational acceleration of the planet. Also determine the value of the gravitational acceleration of the planet that is three planetary radii away from the surface of the planet.

2007-12-16 02:05:17 · 3 answers · asked by Franny 3

Which one would you pick?

2007-12-16 01:30:11 · 9 answers · asked by Mr. Cloud 2

A train traveling at a constant speed rounds a curve of radius 350 m. A chandelier suspended from the ceiling swings out to an angle of 15.0° throughout the turn. What is the speed of the train?

I got 91.63 m/s when I first tried, which according to my online guide is wrong?

2007-12-16 01:22:12 · 1 answers · asked by hahahahahaha 1

2007-12-16 01:14:07 · 6 answers · asked by Anonymous

2007-12-16 01:03:55 · 2 answers · asked by Anonymous

How do i do this? What type of velocity do i take in account? and what is the displacement that i should be taking into the formula of velocity?
any help on this would be welcome as i am totally all out on it.

thx in advance for reading my question

2007-12-16 01:02:29 · 2 answers · asked by harrow 2

I have a project in physics and i need procedures how to do it

I dont know what its called but it somehow looks like this

http://www1.istockphoto.com/file_thumbview_approve/1550408/2/istockphoto_1550408_collision_balls_5.jpg

Please help me i need to do it tomorrow i need to make one not buy one thanks

2007-12-16 00:44:06 · 2 answers · asked by hannah 4

until I start to travel backwards is there a point in between where I can be considered motionless?

2007-12-15 23:22:05 · 8 answers · asked by eazylee369 4