A 78.0 kg hoop rolls along a horizontal floor so that its center of mass has a speed of 0.190 m/s. How much work must be done on the hoop to stop it?

When a DC current passes through the coil, it will produce a magnetic flux around the coil. Is this the reason why the coil get heated? Because the magnetic flux will be stable after all as DC current does not oscillate?

The deuteron is a bound state of a proton and a neutron of total angular momentum j = 1. It is known to be principally an S(ℓ = 0) state with a small admixture of a D(ℓ = 2) state. Calculate the magnetic moment of the pure d state n-p system with j = 1. Assume that the n and p spins are to be coupled to make the total spin s which is then coupled to the orbital angular momentum ℓ to give the total angular momentum j. Express your result in nuclear magnetons. The proton and neutron magnetic moments are 2.79 and -1.91 nuclear magnetons, respectively.
Note: The nuclear magneton is given by
µ = [(gℓℓ + gss) · j] j(j + 1) jµ0

2 questions thx

1) A point source emits sound waves isotropically. A sound meter measures a sound level of 51.72 dB at location C and a sound level of 45.53 at location D, a distance of 16 m from location C. The two locations C and D and the point source are all located along the same line. How far from location C is the point source? Give your answer in m, though enter only the numerical part in the box.

2) A point source emits sound waves isotropically. A sound meter measures a sound level of 51.21 dB at location C and a sound level of 47.79 at location D, a distance of 15 m from location C. The two locations C and D and the point source are all located along the same line. What is the total output power emitted by the point source? Give your answer in mW, though enter only the numerical part in the box.

A.) What is a power law? What does it mean for a quantity like the electric field to drop off as a power law?

B.) Does the electric field always drop off as r^-2, or can it drop off faster?

C.) Can the Coulomb force do work on a mass? What is required for this to happen?

A helium-filled toy balloon has a gauge pressure of 0.350 atm and a volume of 8.0 liters. How much greater is the internal energy of the helium in the balloon than it would be at zero gauge pressure?__________J

Please show all work to get credit.

A photographic slide is to the left of a lens. The lens projects an image of the slide onto a wall 7.00 m to the right of the slide. The image is 73.5times the size of the slide.

(a) How far is the slide from the lens?
________ m

(b) Is the image erect or inverted?

erectinverted    

(c) What is the focal length of the lens?
_______ m

(d) Is the lens converging or diverging?

convergingdiverging   

7) While pushing a cart across a floor, Andrea and Jennifer exert forces ?? and ?? on the cart. Andrea’s

force is due north with a magnitude of 130.0 N and Jennifer’s force is 32° west of north with a magnitude of 180.0 N. (a) Find the net force in component form. (b) Find the magnitude and direction of the net force. (c) If Andrea and Jennifer’s housemate, David, disagrees with the move and wants to prevent its relocation, with what force should he push with so the cart does not move? (assume there is not friction on the cart)

8) A car with a mass of 1000.0 kg accelerates from 0 to 90.0 km/h in 10.0 s. (a) What is its acceleration? (b) What is the net force on the car?

9) A body of mass ? moves in a horizontal direction such that at time t its position is given by
?(?) = ? cos(?? + ?) where ?, ?, and ?are constants. What is the time dependent force acting on the body

Calculate the curls of: ? ×V~ = [?yVz ??zVy] xˆ +[ ?zVx ??xVz] yˆ+ [?xVy ??yVx] zˆ  

(b) V= y xˆ + z yˆ + x^2 zˆ

The magnitudes of F1, F2 and F3 are 300, 190 and 250 N, respectively. F1 is directed on the slope m =
0.6 m/m. F2 is directed alpha = 0.17 radians from F1. F3 is directed beta =123 degrees from F2.
Determine the direction of the Resultant in degrees measured counter-clockwise from the + x-axis.

A car initially traveling at 40 m/s runs out of gas while traveling up a slope. It coasts for a distance of 500 m before it starts to roll back down.

a. What is the acceleration of the car?

b. What is the angle (incline) of the slope?

c. How long does it take after the car runs out of gas before it starts to roll back down?

d. Once the car starts rolling backwards, how long does it take before it passes its starting point, 500m down the slope?

We wish to coat flat glass (n = 1.50) with a transparent material (n = 1.31) so that reflection of light at wavelength 500 nm is eliminated by interference.

(a) What minimum thickness can the coating have to do this?

(b) What is the next thickness for which destructive interference would occur?

One form of nuclear radiation, beta decay, occurs when a neutron changes into a proton, an electron and a neutral particle called a neutrino. When this change happens to a neutron within the nucleus of an atom, the proton remains behind in the nucleus while the electron and neutrino are ejected from the nucleus. The ejected electron is called a beta particle. One nucleus that exhibits beta decay is the isotope of hydrogen ³H, called tritium, whose nucleus consists of one proton (making it hydrogen) and two neutrons (giving tritium an atomic mass m = 3u). Tritium is radioactive, and it decays to helium.

Suppose an electron is ejected from a ³H atom, which has a radius of 1.000×10^-14 m. The resulting ³He atom has the same radius as the ³H atom. What is the escape velocity of the electron ejected from the process?

Note: Your answer may be larger than the speed of light which is okay in this scenario.

with a velocity v = 4.6i m/s. It the strikes the six ball, which has an identical mass and is initially at rest. After the collision the eight ball is deflected by an angle of θ = 26° and the six ball is deflected by an angle of Φ = 35°, as shown in the figure.

Part (a) Write an expression for the magnitude of six ball's velocity, in terms of the angles given in the problem and the magnitude of the eight ball's initial velocity, v.

Part (b) What is the magnitude of the velocity, in meters per second, of the six ball?

Part (c) What is the magnitude of the velocity of the eight ball, in meters per second, after the collision?

A ball of mass, m is thrown straight up and rises h after leaving your hand, it momentarily stops. Acceleration due to gravity g is downward. Ignore air resistance.

Part A (5 points): If the ball is the system, and the Earth is the surroundings, what is the change in potential energy, ΔUsys of the system, and what is the work done, Wsurr by the surroundings ?

Δ Usys = 0; Wsurr = -mgh

Δ Usys = mgh; Wsurr = -mgh

Δ Usys = mgh; Wsurr = 0

Δ Usys = 0; Wsurr = 0

Δ Usys = -mgh; Wsurr = 0

Part B: If the ball + Earth is the system, and nothing is in the surroundings, what is the change in potential energy, ΔUsys of the system, and what is the work done, Wsurr by the surroundings ?

Δ Usys = 0; Wsurr = 0

Δ Usys = mgh; Wsurr = -mgh

Δ Usys = mgh; Wsurr = 0

Δ Usys = 0; Wsurr = -mgh

Δ Usys = -mgh; Wsurr = 0