Contact Definition and 422 Threads

have absolutly no idea where to put this but ill put it here My eyesight is something like +6.25/+6.50 Now the eye man (optomotrist?) said that they only make contact lenses that go up to +6. I was wondering why this is? Also why can't long sighted people have laser eye sugery? Is there...

As shown in the attachment, the link (blue) is connected to two pins A and B (red). Force is applied by the pin A on the link along the x direction purely. A reaction force is expected at the corresponding point of contact between the pin B and the link I am told that the compressive...

If I came into accidental contact with a radioactive substance, and it got say on my hands and watch. Obviously I can wash my hands off, but also could I ujust wipe the contamination off the watch? Or would it remain contaminated? Thanks.

Another spinoff from the uncontacted tribes thread. A couple of arguments/points were made about leaving uncontacted tribes alone: -The history of intervention has, to put it mildly, not been good. -If we follow some version of Star Trek's "prime directive", we should let them develop in...

Homework Statement While investigating the contact times between a golf club and a golf ball, a student wanted to measure the contact times between metal objects – looking at how various factors (such as the material from which they were made, their mass, their speed on impact) affected the...

Homework Statement i hit a golf ball of mass 0.045kg with an avg. Force of 2.5x10^3 N over a short time interval of 1.0 x 10^-3 s at an angle of 30 degrees with respect to the horizontal. neglect air resistance and assume a level course. What is the speed of the ball immediately after...

I'm just wondering why PMMA (polymethylmethacrylate) is hydrophobic and does not attract water. I can't find anything that explains this on a molecular level :S

Contact Stress? I have a "High Spin" rolling system that spins pipe to compact cement lining. We are using tandem 7-14.5LT D/8 bias-ply tires on each end of the axles with the pipe riding in the saddle between two sets of tires. The tires are running approx. 70 MPH for just over a min. The...

[SOLVED] Contact Lenses Problem Homework Statement A contact lens is made of plastic with an index of refraction of 1.58. The lens has a focal length of +26.0 cm, and its inner surface has a radius of curvature of +20.0 mm. What is the radius of curvature of the outer surface? Homework...

I am designing a spinal disc with 2 metal endplates. These endplates are rectangular in shape and are fixed to form a flat contact surface with the vertebrae bone surface. My question is based on the bending stress of these metal endplates. I need to work out the possible thickness of these...

Homework Statement Three blocks are in contact with each other on a frictionless, horizontal surface, as in Figure P5.54. A horizontal force F is applied to m1. Take m1 = 2.00 kg, m2 = 3.00 kg, m3 = 4.00 kg, and F = 22.0 N. (c)What is the magnitude of the contact force between m1 and m2...

Two blocks are in contact on a frictionless table. A horizontal force F is applied to M2, as shown. If M1 = 1.51kg, M2 = 3.96kg, and F = 4.55N, find the size of the contact force between the two blocks. So first I found the acceleration (F=ma) 4.55/(1.51+3.96) = 0.83 = acceleration Im...

[SOLVED] Contact Force Homework Statement a.Two blocks are in contact on a frictionless table. A horizontal force F Is applied to M[SIZE="1"]2. The force's magnitude is 4 N. [The diagram shows the force pushing on the left side of M[SIZE="1"]2, which has M[SIZE="1"]1 on its right side.]If...

Let's say we have a charged plastic rod and a neutral metal ball, and a charged metal rod and neutral metal ball, which rod can transfer more charge onto the metal ball? Or metal ball onto the rod (if the rods are positive) Thank you

"contact" by carl sagan I hear they are showing Cosmos by carl sagan again on tv but something else of carl sagan's worth knowing about is his novel "contact". If you don't have time to read the book watch the film staring Jodie Foster and Mathew McConnaughey - it is awesome, and the best film...

I am familiar with Hertzian contact mechanics for spheres in contact with a falt surface or a sphere in contact with another sphere. However, I am unsure on how to model a ball and socket contact? Could anyone help me with this idea please? Thanks

Homework Statement A mountain climber is rappelling down a vertical wall. The rope attaches to a buckle strapped to the climber's waist 15 cm to the right of his center of gravity and makes an angle of = 15° with the wall. The climber weighs 780 N. (a) Find the tension in the rope N...

are contact lenses dangerous for eyes? i hate glasses. another question is that is there any contact lenses which are colored and also do glasses job too?

HI All: Using Hertz contact formula I calculated contact stress for cylinder in contact with cylinderical socket but I don't know to which stress to compare this contact stress.Actally I comapred with material bearing stress & calculated stress was less that bearing stress(got margin of...

Laydies and Gents can anyone help me here? suppose there are well known formulas for this. That is, contact area of a known size cylinder lying inside a larger know size cylinder... hope problem is clear thank you best regards martin

Homework Statement A car of mass 8.50E+2 kg and a truck of mass 3.55E+3 kg run into one another due to ice on the road. 60.0 ms after the collision, the car is pushing on the truck with a force whose magnitude is 1.56671E+5 N. Calculate the size of the force on the car due to the truck at...

When you touch something there isn't really any "physical" contact When you touch something there isn't really any "physical" contact, it's just the electromagnetic forces that repel each other. So if I try to touch a table, no particles from my hand actually touches any particles from the...

dont have much time, ll make it quick does friction depends on area of surface of contact?? i don't think it does:confused::confused:

Which contact lenses do you like the most? For me it's 'Day and Night' although I take it out in the night just to let the eyes breathe better.

Hello, I need a contact form on my website, that will send to my email address what the visitor enter in the form fields. The problem is that I can't run any php scripts.. is there a way to use some html form? :smile:

Three blocks are in contact with each other on a frictionless horizontal surface with m1=1kg m2=2kg m3=3kg A horizontal force of 24N is applied to M1. a) Find the acceleration of the three blocks b) Find the net force on each block c) Find the magnitude of the contact forces...

Hi, when two cylinders in contact, but not parallet to each other (skewed), are rotating, there is a development of forces between them which tends to push one cylinder along its rotation axis and the another one to the opposite side. In other words, there will be translation movement between...

Homework Statement A student is reading a lecture written on a blackboard. Contact lenses in her eyes have a refractive power of 57.50 diopters; the lens-to-retina distance is 1.750 cm. (a) How far (in meters) is the blackboard from her eyes? (b) If the writing on the blackboard is 5.00 cm...

Homework Statement Without her contact lenses, a student can focus an object located 0.80 m to infinity from her eyes. The power lens, measured in diopters, is the reciprocal of the focal length, measured in meters. Assuming that the image distance in the eye is 0.02 m, what lens power does...

Homework Statement I'm unable to understand the production of dark fringe in the central point of contact of lens.The text says "the path difference between the rays reflected at the top & bottom of air gap at the point of contact is zero.Actually the ray reflected from the top of air film...

Suppose you let identical pith balls come in contact to make q1=q2. Would the charges be equal if the pith balls were of different size?

Homework Statement A 1.2- kg hammer hits a nail at a speed of 15 m/s and rebounds at 60 percent of that speed. The resisting force of the nail is 9000 N. Approximately how long is the hammer in contact with the head of the nail? Homework Equations P=mv Pf-Pi=Ft The Attempt at a...

Homework Statement A .145 kg pitched baseball moving at 35 m/s strikes a bat and is popped straight up (forming a 90 degree angle)to a height of 55.6 m before turning around. If the contact time is .50 seconds. calculate the average force on the ball during contact. Homework Equations...

If two objects collide with each other, where is contact actually made? This question confuses me because even at the atomic level (two atoms colliding) where is contact made? P.s. i hope I'm in the right section of the forum

Hi, I have been working on this for a little while and think I am approaching it incorrectly. If someone can help, I'd really appreciate it. This is for a basic introductory calculus based Physics class that I am in. 1. Mathematically demonstrate the following equation with no numerical...

Ok so the question is, "A skier of mass 60kg, initially at rest, slides down from the top of a frictionless, icy, hemispherical, mountain with a radius of curvature R of 100m. a)Draw a free body diagram and write the Newton's Equations at the moment when he/she is at some point below the...

Does anyone have resources for how long a foot is in contact with a football. Numbers I have found, but video or set of pictures with time on it would help. Please and thank you.

A 57.0 g tennis ball with an initial speed of 25.2 m/s hits a wall and rebounds with the same speed. The figure below shows the force of the wall on the ball during the collision. What is the value of Fmax, the maximum value of the contact force during the collision, if the force is applied for...

A woman is straining to lift a large crate, without success. It is too heavy. We denote the forces on the crate as follows: P is the upward force being exerted on the crate by the person, C is the contact force on the crate by the floor, and W is the crate’s weight. How are the magnitudes of...

I'm really confused about this problem - As shown in Figure 5-22, a force of magnitude 7.50 N pushes three boxes with masses m1 = 1.30 kg, m2 = 3.30 kg, and m3 = 5.10 kg. (a) Find the magnitude of the contact force between boxes 1 and 2. (b) Find the magnitude of the contact force...

Hi I have a problem and a doubt regarding Newton's laws of motion. Consider three blocks of 5,2,5kg respectively placed one over the other and dropped from the top of a tower. (the 5 kg if at the top, 2kg in the middle and the 5kg at the bottom). i) Find the acceleration of each block...

What is the best way to estimate or measure the duration of a contact in a collision? I have a stick applying a 1.5 N force onto a stationary plastic box. Assuming that the plastic is incompressible, how long will the time have elapsed before the stick with 1.5 N no longer has an effect on...

This is a long shot, but maybe someone will know or can point me in the right direction. I'm looking for an experimental value for the contact angle between tetrahydrofuran (THF) with both mica and graphite substrates. I've done numerous googling and also did a search on the web of knowledge...

Now, my textbook says that force of friction is independant from the area of contact. But, when the tyres of my bicycle get deflated i have to exert extra force than otherwise. Why?

Assume I am holding a bar parallel to the ground. I let go of the bar and it lands on something at an arbitrary point on the bar before it hits the ground. How much force is dealt to the object (and bar)? This is the problem, but I'm going to simplify it to make a calculation possible. First...

Is it okay to wear more than one in each/either eye?

How can I contact a University for funding for a project. The project is on fuel cells, and I plan on building two prototypes; one following the instructions precisely, the other for experimenting with nickel catalysts. I have a estimate of $75-$100 CDN. Thanks for any help, Pierre.

I am having a hard time trying to figure out this problem: What is the max speed that you can drive the car over the top of the bump without losing contact with the road. I have the radius= 66.7 m, constant speed of car = 16.4m/s, and weight of your passenger=57.0kg. With these numbers I was...

Hello, I have a problem and I would like to check my answers: A mass m1 rests on top of another mass m2 , which in turn rests on a frictionless horizontal surface. A light cord is attached to m2 ,which is used to pull on it witha force F. a) Find the acceleration ofeach object when...

Question: A typical white dwarf has a mass of 1 solar mass and a radius of 10 thousand km. A typical neutron star has a mass of 1.5 solar masses and a radius of 30km. Given that there's a natural speed limit in Nature, namely the speed of light, is it possible to have a contact binary...