# distance

a
2. ### Trying to use polar coordinates to find the distance between two points

${dx}^2+{dy}^2=3^2+3^2=18$ ${dr}^2+r^2{d\theta}^2=0^2+3^2*(\theta/2)^2\neq18$ I have a feeling that what I'm doing wrong is just plugging numbers into the polar coordinate formula instead of treating it as a curve. For example, I naively plugged in 3 for r even though I know the radius...
3. ### Born-Oppenheimer approximation & distance

According to the Born-Oppenheimer approximation, what does the internuclear distance Req depend on? Atomic number Z? Rotational Energy of the nuclei? Electrons' kinetic energy? Coulomb interaction between the two nuclei? Coulomb interaction between the electrons? Vibrational energy of the...
4. ### B Finite distance between two points

If X is a metric space, what is the simplest sufficient condition for d(x,y)<∞, ∀ x, y ∈ X?
5. ### I Infer the distance of a closest neighbor galaxy from correlation

I am trying to estimate the distance of closest galaxy neighbor knowing the expression of number of neighbors into a volume $\text{d}V$, the mean density $n_\text{gal}$ and the correlation function, i.e with this expression : $\text{d}N=n_{\text{gal}}\,\text{d}V\,(1+\xi(r))$ with...
6. ### Decreasing size of person's shadow as they walk toward a lamp

1. Homework Statement If a man of height 6ft moves with 5ft/sec velocity towards a lamp hanging at 15ft height, then at what rate his shadow will decrease? 2. Homework Equations Not sure but dynamic equations can help. 3. The Attempt at a Solution I have no idea about how I can approach.So...
7. ### I General Q: How do you measure a Galaxy's distance?

If I am given the variable of time (observed), and diameter is it possible to measure the distance of a galaxy? Or do I need more variables? Just trying to figure out the most simple way to go about doing something like that.
8. ### Force at a Distance

Hello, I am trying to support a shelf with a block of wood. The block of wood is only 3 inches deep and the shelf 2 feet deep. If the block of wood is capable of supporting 500 lbs, how much weight can the shelf support if the force is applied downward at the edge of the shelf? This is a real...
9. ### Defining velocity as a function of distance

1. Homework Statement The equation is given: v = f(t) = (mg/b)(1 - e^((-b/m)t)) Where v is velocity, m is mass, g is 9.81 and b is a constant of proportionality I need to find the function k(x), where x is distance from said body's initial position. 2. The attempt at a solution v = f(t) =...
10. ### What is the operation principle of the LDR?

1. Homework Statement Construct suitable circuit and record your finding to illustarte the operational principle of the sensors: sound, light Results: Distance from light source (cm) - light intensity (lx) 0 - 1000 10 - 400 20 - 260 30 - 200 40 - 190 50- 180 experiment involved moving a...
11. ### A Accelerometer question: Monitoring hand movements during practice surgical procedures

I'm a surgeon, maths and physics study was a long time ago. I have been working on a project using an accelerometer and gyroscope.to.monitor hand movements during practice procedures. I thought to represent my 3 axis acceleration as a vector and then subtract from this 1g, to compensate for...
12. ### Find the distance from the point P to a line - linear algebra

1. Homework Statement Find the distance from point P (1,7,3) to the line (x,y,z) = (-2,1,4) + s(1,-3,4), s is a free variable 2. Homework Equations projnQP = ( QP⋅n/(lengthQP)(lengthn) )(n) 3. The Attempt at a Solution I'm not quite sure about how to find the normal (n) here, but if I make...
13. ### Displacement given the acceleration

1. Homework Statement How could I get the distance traveled by a vehicle having only its constant acceleration as data? 2. Homework Equations I know that the acceleration is the derivative of the velocity and the velocity is the derivative of the position. 3. The Attempt at a Solution I...
14. ### Inteference Fringes of Double Slit Experiment in Water

1. Homework Statement Suppose a double-slit experiment is immersed in water (with an index of refraction of 1.33). When in the water, what happens to the interference fringes? 2. Homework Equations λ = λ0 / n y = (λmL) / d d = distance between slits L = distance to viewing screen n = index...
15. ### Work to move electron/proton between the plates of a charged capacitor?

1. Homework Statement A charged capacitor consists of two large flat plates, one with positive charge +Q and the other negative charge -Q. An external agent trans an electron from the positive plate to the negative and also transfers a proton from the negative plate to the positive plate. There...
16. ### B Basic average acceleration confusion

Hi there, I'm struggling to distinguish why the following two equations are giving distinct answers, when the question explicitly states either could be used: v=u+at v^2=u^2+ad when v=12 m/s u=0 m/s a (average acceleration)= the unknown variable d=24 m t=4s Theoretically, the two should...
17. ### B Using trig to find distance?

Hi there! I haven't yet taken a trigonometry course (I'm in High-school), but I have an amateur interest in surveying. Recently I began thinking about how I could calculate the height of a point relative to me, or the distance of the object from me. Naturally, I immediately thought of the...
18. ### How can I find this displacement?

1. Homework Statement Your task is to estimate how far an object traveled during the time interval 0≤t≤8, but you only have the following data about the velocity of the object. *First image You decide to use a left endpoint Riemann sum to estimate the total displacement. So, you pick up a blue...
19. ### Calculating distance from speed

1. Homework Statement The speed of a runner increased during the first three seconds of a race. Her speed at half-second intervals is given in the table. Find lower and upper estimates for the distance that she travelled during these three seconds. It follows the image's square. 2. Homework...
20. ### I Minimum number of moves from a to b

Hi, I think this is a topology question, but I'm honestly not 100% sure. Feel free to move. On a number line, I am trying to find the minimum number of moves to get from one point to another, given certain allowed step sizes. For example, My allowed steps might be +/-2, +/-3, and I want to move...
21. ### I What is distance?

I have taken physics to Modern so I understand the basics of time and distance dialation. I don't understand what is distance is. It is always given by reference to something else, or tied together like in space time. The closest I've gotten to something I can understand, and answers my question...
22. ### I Finding a bullet's velocity over time

Hi, I engage in physics as a hobby, and I'm not extremely familiar with things reaching into calculus levels of math. That said, how would I find the velocity of a bullet at a given time or distance, taking wind/humidity/etc. out of the equation? I know the muzzle velocity only applies to the...
23. ### Calculating for a distance including vi, vf, time, and Ff

1. Homework Statement For a project we have to find a movie scene and calculate using any variables we can find. I am using Back to the Future and want to calculate the distance the DeLorean travels in one of the first scenes when they're first using it. I'd also like to find the acceleration...
24. ### B Distance between the Earth and The Moon

we know that the moon is far away the distance between us and the moon can fit all the other 7 planets and some small dwarf planets but how ? it would take us 3 days to reach the moon and the spacecraft were traveling in at least 240,000 miles it should take us more than a year to reach the...
25. ### Height of an island beyond the horizon

1. Homework Statement If I am standing on the ocean shore, and my eye level is 6 feet above sea level, how far above the horizon would an island appear that is 15 miles away and whose highest point is 200 feet above sea level (assuming the earth’s diameter is 3,960 miles?) In other words, how...
26. A

### Uniform Circular Motion - distance

1. Homework Statement An object with mass m = 2 kg is moving in a uniform circular motion with radius r = 2m as shown in the figure. It takes π seconds for the object to travel from θ =0 to θ = 180 degrees. What is the distance travelled by the object in 20 s? 2. Homework Equations s = rq...
27. M

### Finding speed when given deceleration and distance?

Hi! I have this homework problem that has me completely stumped. Any help is greatly appreciated! In coming to a stop, a car leaves skid marks 80m long on the highway. Assuming a deceleration of 7.00m/s2, estimate the speed of the car just before braking. I just can't figure out what formula...
28. ### Distance of two moving particles

1. Homework Statement There are two particles. There are moving equally on two intersecting lines to intersection. On time t=0 is the distance of two particles d. The velocity of one particle relative to the other has a projection u in the direcion of d. In direction perpendicular to d is the...
29. G

### What time did they both set off?

1. Homework Statement Willy leaves point A and Milly leaves point B, both of them are heading toward each other's starting point. They both have constant speeds, but Milly is faster, and they pass each other at noon without stopping. Milly arrives at point A at 1:00 pm, and Willy arrives at...
30. S

### B Constant acceleration changes direction twice

Hello, I just did a practice physics problem that asked if an object with constant acceleration can change direction twice. The answer was no. What if you had an object attached to a string spinning at constant velocity. Is the tangential acceleration constant?