Find the thickness of film of a camera lens coating that minimizes normal reflection in the wavelength range 400 nm to 700 nm. Assume refractive index of film nfilm=1.38 and nglass=1.50

A current I flows to the right through a rectangular bar of conducting material, in the presence of a uniform magnetic field B pointing out of the page.

a) If the moving charges are positive, in which direction are they deflected by the magnetic field? This deflection results in an accumulation of charge on the upper and lower surfaces of the bar, which in turn produces an electric force to counteract the magnetic force. Equilibrium occurs when the two exactly cancel. (This phenomenon is called the Hall effect).

b) Find the resulting potential difference (the Hall voltage) between the top and bottom of the bar, in terms of B, v (the speed of the charges), and the relevant dimensions of the bar.

c) How would your analysis change if the moving charges were negative? [The Hall effect is the classic way of determining the sign of the mobile charge carriers].

18.43---- a) You warm 2.00 kg of water at a constant volume from 19.5 ∘C to 31.0 ∘C in a kettle. For the same amount of heat, how many kilograms of 19.5 ∘C air would you be able to warm to 31.0 ∘C? Make the simplifying assumption that air is 100% N2.

b)What volume would this air occupy at 19.5 ∘C and a pressure of 1.20 atm ?

When a thermometer is inserted into hot water, the mercury or alcohol is sometimes observed to fall slightly before it rises. Why?

Two point particles separated by 0.8 m carry a total charge of 185

A wing of area 1.5 ft2 and aspect ratio of 6 is tested in a subsonic wind tunnel at a velocity of 77 knots at standard sea level conditions. At an angle of attack of -1 degree, the measured lift and drag are 0 and 0.181 lb, respectively. At an angle of attack of 2 degrees, the lift and drag are measured as 5.0 and .23 lb, respectively. Calculate the span efficiency factor (i.e. Oswald efficiency factor).

1) A concrete highway curve of radius 70 m and is banked at an angle of 30o. Imagine a car driving around the turn at a constant height. We want to find the maximum speed at which a 1100 kg rubber-tired car can go around this curve. Take the static coefficient of friction of rubber on concrete to be ?s = 1.0.

a) Calculate the maximum speed the car can go around the curve.

b) Discuss what is different from finding the maximum to finding the minimum speeds.

c) Calculate the minimum speed the car can go around the curve

2) On a rainy day, the concrete will be wet and reduce the coefficient of friction to ?s = 0.3

a) Calculate the maximum speed the car can go around the curve.

b) Calculate the minimum speed the car can go around the curve.

3) Freezing rain! The coefficient of friction is now zero! Can a car theoretically make it around this turn? If not, explain why not. If so, calculate the speed(s) at which they will be able to make it around the curve.

A small 0.11 kg metal ball is tied to a very light (essentially massless) string that is 0.9 m long. The string is attached to the ceiling so as to form a pendulum. The pendulum is set into motion by releasing it from rest at an angle of 60 ∘ with the vertical.

A) What is the speed of the ball when it reaches the bottom of the arc?

B)What is the centripetal acceleration of the ball at this point?

C)What is the tension in the string at this point?

A camera of weight 8 newtons is dropped from a drone at a height of 19.9 meters and enters free fall. Assuming no air resistance, what is the final velocity of the camera a moment before it shatters on the ground?

A straight, vertical wire carries a current of 1.25 Adownward in a region between the poles of a large superconducting electromagnet, where the magnetic field has a magnitude of B = 0.560 Tand is horizontal.

Part A

What is the magnitude of the magnetic force on a section of the wire with a length of 1.00 cm that is in this uniform magnetic field, if the magnetic field direction is east?

B

What is the direction of the magnetic force on a section of the wire with a length of 1.00  that is in this uniform magnetic field, if the magnetic field direction is east?

Part C

What is the magnitude of the magnetic force on a section of the wire with a length of 1.00 cm that is in this uniform magnetic field, if the magnetic field direction is south?

D

What is the direction of the magnetic force on a section of the wire with a length of 1.00 cm that is in this uniform magnetic field, if the magnetic field direction is south?

Part E

What is the magnitude of the magnetic force on a section of the wire with a length of 1.00 cm that is in this uniform magnetic field, if the magnetic field direction is30.0 ∘ south of west?

Part F

What angle will the magnetic force on this segment of wire make relative to the north, if the magnetic field direction is 30.0 ∘ south of west?

A 1.02 kg block is kept stationary on a 45 degree slope by applying a horizontal force F onto it. What is the minimum value of F if the coefficient of static friction is 0.5?

a) 3.33 N

b) 2.56 N

c) 4.25 N

d) 6.40 N

16. On a frictionless horizontal air table, puck A (with mass 0.255 kg ) is moving toward puck B (with mass 0.375 kg ), which is initially at rest. After the collision, puck A has velocity 0.125 m/s to the left, and puck B has velocity 0.649 m/s to the right.

Part A: What was the speed vAi of puck A before the collision?

Part B: Calculate ΔK, the change in the total kinetic energy of the system that occurs during the collision.

In its daily prowl of the neighborhood, a cat makes a displacement of 128m due north, followed by a 70m displacement due west.
a) Find the (a) magnitude and (b) direction of the displacement required for the cat to return home.
b) If, instead, the cat had first prowled 70m west and then 128m north, how would this affect the displacement needed to bring it home? Explain.

An energy plant produces an output potential of 2700 kV and serves a city 202 km away. A high-voltage transmission line carries 460 A to the city. The effective resistance of a transmission line [wire(s)] is 1.69 Ω/km times the distance from the plant to the city. 1) Assume the plant charges $ 0.105 /kW · hr for electric energy. At this rate, how much does it cost to transmit energy to the city (by the transmission line heating the atmosphere) each hour? Answer in units of dollars/hr. 2) Consider the money lost by the transmission line heating the atmosphere each hour. Assume the energy plant produces the same amount of power; however, the output electric potential of the energy plant is 20% greater. How much money per hour is saved by increasing the electric potential of the power plant? Answer in units of dollars/hr