Two point charges, -62.5 microcoulombs (placed on the left side of the positive charge) and +12.5 microcoulombs, fixed on the x-axis, are seperated by a distance of 25.0 cm from each other. At what points along the x-axis is the electric potential equal to zero? (A well-labeled sketch showing these points is required Find the voltage at a point on the x-axis, 15.0 cm to the left of the negative charge.

Two parallel electrical conducturs each leads a current of the same size. The distance between the center of the conductors can be varied from 100 mm to 1000 mm. The currents are going in the same directions in both of the conductors and have a value of I=19 A.

1. Calculate the force per meter (F/l) between the conductors in their plane and plot F/l against the distance between them (100 mm to 1000 mm) in a graph. Do not take to few points.
2. Show if there is a repelling or attractive force between the conductors.

Which of the following statements are true about relativistic mass, momentum and energy?

T or F? according to Einstein, a particle at rest has no energy at all

T or F? if a particle of rest mass m0 were entirely converted into energy, it would yield an energy of (m0)(c^2)

T or F? if it were possible to accelerate a particle near the speed of light, its relativistic mass would approach infinity

T or F? the relativistic expression for kinetic energy is the same as the classical (non-relativistic) equation for kinetic energy

T or F? when a particle moves at high speed, its relativistic mass is the same as its rest mass

A certain ultrasound device can measure a fetal heart rate as low as 50 beats per minute. This corresponds to the surface of the heart moving at about 4.0 x 10-4 m/s. If the probe generates ultrasound that has a frequency of 2.0 MHz (1 MHz = 1 megahertz = 106 Hz), what frequency shift must the machine be able to detect? Use v sound = 1540 m/s for the speed of sound in human tissue.

On Myth Busters it was determined that a penny dropped from the top of the Empire State Building would reach a terminal velocity of 64.4 miles per hour before hitting the ground. What is the height of the building in feet needed for a penny with a mass of 2.5 grams to reach a velocity of 46.7 miles per hour? Assume that no energy is lost from frictional drag. For the acceleration of gravity on the Earth us 9.81 meters per second squared or 32.2 feet per second squared.

In procedure 2: suppose red light passes through a double slit and falls on a screen. In the diffraction pattern, the distance from the central maximum to the first maximum is 5 mm.

a) The distance from the first minimum (dark spot) to the second minimum in the diffraction pattern is

between 7.5 mm and 10 mm

less than 2.5 mm    

more than 10 mm

between 2.5 mm and 5 mm

exactly 2.5 mm

between 5 mm and 7.5 mm

exactly 5 mm

exactly 7.5 mm

exactly 10 mm

b) Blue light has a higher frequency than red light. If you switch the light falling on the double slit from red to blue

the distance between the maxima decreases, the number of maxima on the screen remains the same

the distance between the maxima increases, the number of maxima on the screen decreases    

the distance between the maxima increases, the number of maxima on the screen increases

the distance between the maxima decreases, the number of maxima on the screen decreases

the distance between the maxima remains the same, the number of maxima on the screen increases

the distance between the maxima remains the same, the number of maxima on the screen remains the same

the distance between the maxima decreases, the number of maxima on the screen increases

the distance between the maxima increases, the number of maxima on the screen remains the same

the distance between the maxima remains the same, the number of maxima on the screen decreases

c) Diffraction experiments are usually done with diffraction gratings (which have many slits) instead of a double slit. The advantage of the diffraction grating over a double slit (using the same screen distance and slit width) is

there are many more maxima generated

it eliminates the central maximum    

all the maxima are farther apart

all the maxima are closer together

all the maxima are brighter

less light goes to the central maximum, and more to the other maxima

d) For this question, there is more than one correct answer. To get this question right, you must select all the correct answers!
You can change L (the distance from the slits to the screen), d (the distance between the slits) and λ (the wavelength of the light used). Which combination would double the distance between the maxima?

double L, leave λ and d unchanged

halve d, leave L and λ unchanged

halve L, halve d, halve λ

halve L, leave d and λ unchanged

double L, double λ, leave d unchanged

double λ, leave L and d unchanged

double d, halve L, leave λ unchanged

halve d, double λ, double L

double L, double λ, double d

halve d, double λ, leave L unchanged

double L, double d, leave λ unchanged

double L, halve d, leave λ unchanged

e) Suppose you are doing a double slit diffraction experiment with monochromatic (single frequency) light. Suddenly the atmosphere changes from air to a gas with a higher index of refraction. What will happen to the pattern?

the distance between the maxima will increase, the color of the light will change to a lower frequency

the distance between the maxima will decrease, the color of the light will remain the same    

the distance between the maxima will remain the same, the color of the light will change to a higher frequency

the distance between the maxima will increase, the color of the light will change to a higher frequency

the distance between the maxima will increase, the color of the light will remain the same

the distance between the maxima will remain the same, the color of the light will change to a lower frequency

the distance between the maxima will decrease, the color of the light will change to a lower frequency

the distance between the maxima will remain the same, the color of the light will remain the same

the distance between the maxima will decrease, the color of the light will change to a higher frequency

Imagine you and your friends are running in the neighborhood like electrons flowing through a circuit. Makeup stories that would serve as analogies for a parallel versus series circuits. Summarize the similarities and differences between the series and parallel circuits. Include your reasoning about what you think is happening.

Describe the temperature response of resistors in a circuit. Are there any devices which take advantage of this property? If so, explain how they work in terms of the properties of electrons.

A small metal sphere, A, carrying a charge of +15.0 µC is at the origin. An identical sphere, B, carrying a charge of -18.0 µC is at ~xB = 4.0ˆi cm and a third sphere, C, carrying +25.0 µC is at ~xC = 3.0ˆj cm.

(a) Find the total electrical force exerted on sphere A.

(b) Let us view sphere A as a probe charge which we are using to measure the field due to spheres B and C. Use your result from part b) to find the electric field (note that this is a vector) at the origin.

(c) Sphere A is released so that it is free to move. It has a mass of 5.0 g and no forces other than the electrostatic forces found in a) act on it. What is its acceleration at the instant of release?

(d) A short time later will your answer from c) still be the correct acceleration for sphere A?

(e) Spheres B and C are touched together and then returned to their original locations. Sphere A is also returned to its original location. Now what is the force on sphere A?

Wile standing at the edge of the roof of a building, you throw a stone upward with an initial speed of 6.79m/s. the stone is subsequently falls to the ground, which is 12.1m below the point of where the stone leaves your hand. How much time is the stone in the air?

All eyeglass lenses have chromatic aberration. This is usually expressed as dioptric spread. For a typical +6.0 D lens, the focusing power for red light is +5.90 D,the power for green light is +6.00 D, and the power for blue light is +6.10 D. This gives a dioptric spread of 0.20 diopter. Suppose a myopic person is observing a distant object through this lens, and the green light of the image is in perfect focus. Assume a distance s′ = 1.7000 cm.

a. How far in front of or behind the retina is the point of sharp focus for red light?

Express your answer with the appropriate units. Enter positive value if the point of sharp focus is behind the retina and negative value if the point of sharp focus is in front of the retina.

b. How far in front of or behind the retina is the point of sharp focus for blue light?

Express your answer with the appropriate units. Enter positive value if the point of sharp focus is behind the retina and negative value if the point of sharp focus is in front of the retina.

A car travels along a straight east-west road. A coordinate system is established on the road, with x increasing to the east. The car ends up 19 mi west of the intersection with Mulberry Road.

(A) If its displacement was -21 mi , how far from Mulberry Road did it start?

For College Physics. Please explain in paragraph form.

Respond to the following:

• In your own words, explain vector, scalar, speed, velocity, and linear acceleration. Also give examples.

A 10 kg block is placed on an inclined plane that is at an angle of 30 degrees with respect to the horizontal. THe coefficient of kinetic friction between the block and the plane is .1. The block is released from rest at 5m above a spring that is also lying on the plane. The spring has a constant of 50 N/m. What is the max compression of the spring?