# Sandy

### “Wrong” Clothing for the Season?

I see plenty of people (seemingly normal) who wear warm clothes in the summer and summer clothes in the winter. Medically speaking, what is the explanation for this?

2 AnswersOther - Health3 months ago### Electric Fields?

What effect does the SIGN of the central charge have on the magnitude of the electric field and the direction of the electric field?

3 AnswersPhysics4 months ago### Mathematics - Writing an equation for the situation?

One energy-saving idea is to design houses with recessed windows on the side facing the sun. Sunlight will enter the window in winter when the sun’s angle is low but it will be blocked in the summer when the angle is much higher. The highest angle of elevation of the sun occurs at noon in mid-June when the angle of elevation, in degrees, is 23.5 + l, where l is the latitude of the location.

a) Assume that the window shown is designed to block the sun’s rays when the sun is at its highest elevation in the summer. Express the depth, d, in meters, of the recess as a function of latitude, l.

b) Draw the graph of d versus l.

c) Determine the value of d for your latitude.

1 AnswerMathematics4 months ago### Interference in Thin Films?

Angler fish emit light through bioluminescence. An angler fish is swimming in a fish tank that has a film on the inside of the glass. The water in the tank has an index of refraction of 1.10, the film has an index of refraction of 1.21 and the glass has an index of refraction of 1.40. The film is 90.0 nm thick, and is such that the light reflecting back at the angler fish has been minimized. Find the wavelength of the angler fish’s light.

1 AnswerPhysics5 months ago### Single Slits?

If the angle between the dark fringes (nodal lines) on either side of the central maximum is 15 degrees, and the wavelength of the light is 670 nm, what is the width of the single slit?

Physics5 months ago### Double Slit Patterns?

In a ripple tank with two point sources, the distance from a point on the second nodal line is 12 cm to one source and 8.5 cm to the other. Calculate the wavelength of the source waves.

1 AnswerPhysics5 months ago### Double Slit Patterns?

The separation between the nodal lines on a double slit interference pattern using red light of wavelength 650 nm is measured to be 2.0 mm. If the incoming light is then changed to blue light of wavelength 450 nm, calculate the separation between the nodal lines.

Physics5 months ago### Finance - Annuity?

You, have been putting away money for retirement for the last 25 years.

a) How much money would you have had to invest into a savings account that pay 6% per year, compounded monthly, if you want to have $1,000,000 after 25 years?

b) Let's say you were to retire by the time you were 60. You want to be able to draw $3,000 per month until you are 90 from your investments. If the investment earns 6% per year, compounded monthly, how much money will you need to have in the fund by the time you are 60 for this to occur?

3 AnswersPersonal Finance6 months ago### Physics - Dynamics?

During a pond hockey game, a puck accelerates from rest at 5.0 m/s over a distance

of 80.0 cm. The puck then slides with a constant speed for 4.0 s until it reaches a rough section which causes it to stop in 2.5 s.

a. What is the speed of the object when it reaches the rough section?

b. At what rate does the object slow down once it reaches the rough section?

c. What total distance does the object slide throughout its entire trip?

d. What was the average speed of the puck?

1 AnswerPhysics6 months ago### Physics – Inductive Loop?

To facilitate traffic flow, many stoplights now have a sensing system based on inductance to determine if a car is waiting at a red light. If that is the case, the light is then switched to green. In a paragraph explain how the system works.

1 AnswerPhysics6 months ago### Electric Charges and Electric Fields?

Three identical point charges A, B, and C are located in the shape of an equilateral triangle with sides of length 15 cm. What is the net force on B if each charge has a magnitude of −5.0*10^−3 C?

3 AnswersPhysics6 months ago### Universal Gravitation?

A rocket ship is moving away from the earth after having been fired from a launch pad. At what point above the earth's surface will the force of gravity be reduced to ½ of its original value?

3 AnswersPhysics6 months ago### Energy and Momentum Calculations?

2 AnswersPhysics6 months ago### Conservation of Momentum?

A 1000 kg car known to be moving at 65 km/h [W] collided at an intersection with a 3000 kg SUV moving [N]. After the collision, the two vehicles "stuck" together and the police estimate that immediately after impact the car-SUV wreckage moved at 45 km/h. Based on this information, what was the speed of the SUV before the collision?

1 AnswerPhysics6 months ago### Wavelength vs. Frequency?

Since white light is made up of all of the rainbow colors, when it enters a prism and the light bends, the white light spreads out into the different colors of the rainbow, which is of course known as dispersion.

My confusion is this:

When the light wave goes from one medium to another, the frequency of the wave remains UNCHANGED. However, the wavelength CHANGES, causing the wave to change speed as it moves from one medium to another. The larger wavelengths have a greater speed (red and orange), and the smaller wavelengths have a lower speed (blue and violet). Since they have different speeds through the prism, they bend by different amounts as they exit the prism.

To sum up my question: Doesn't the SAME wave in the spectrum have to have the SAME FREQUENCY, and therefore the SAME WAVELENGTH? For example, as the spectrum below indicates, Red has one single wavelength with its corresponding frequency. So how can you reconcile this with an UNCHANGED frequency but a CHANGED wavelength? That won't be Red anymore! Would it?

What am I missing/misunderstanding here?

Can't wrap my head around this at all!

Thanks for your help!

8 AnswersPhysics8 months ago### Not sure how to do the Free Body Diagram for part (C)?

In a physics experiment on static friction, two objects made of identical material are tied together with a string. The first object has a mass of 5.0 kg and the second object has a mass of 3.0 kg. Students measure the maximum force of static friction as 31.4 N to move both objects across a horizontal surface.

(a) What is the coefficient of static friction?

(b) What is the magnitude of the tension in the string if they pull on the first object?

(c) A student pushes the 3.0 kg object with a force of 15.0 [down]. What are the magnitudes of the maximum force of static friction and the tension now?

(d) Will your answers to (c) change if the student pushes down on the 5.0 kg object instead? Explain.

2 AnswersPhysics9 months ago### Conservation of Angular Momentum?

A rubber ball (m = 1 kg, r = 0.5 m) moving at 10 m/s strikes a metal rod (m = 2 kg and length of 1 m) hanging from a pin at its geometric center. After the collision, the rubber ball falls straight to the ground and the rod moves with an initial angular speed of 2 rad/s. At what angle did the rubber ball strike the metal rod? Irod about its center = (1/12)mL2.

1 AnswerPhysics9 months ago