Mary spots Bill approaching the dorm at a constant rate of 2 m/s on the walkway that passes directly beneath her window, 17 m above the ground. When Bill is 120 m away from the point below her window she decided to drop an apple down to him.

A.) How long should Mary wait to drop the apple if Bill is to catch it 1.75 m above the ground, and without either speeding up or slowing down?

B.) How far from directly below the window is Bill when Mary releases the apple?

A common approximation to the interatomic forces in a material is the Lennard-Jones potential between neighboring atoms in a solid:

U(r) = A/r¹² - B/r⁶

This can be used to find various information about a solid material.

Assume that for the lattice of a particular alloy of copper, the Lennard-Jones constants are:

A = 9.08 ⨯ 10^-133 J·m¹²
B = 3.96 ⨯ 10^-76 J·m⁶

Find the following:

(a) The equilibrium distance between neighboring atoms in the copper lattice (this is called the lattice constant a).


(b) Model this as an approximate potential around the equilibrium position

U_eff(r) = (1/2)k(r-a)² + C

(i) What is the effective spring stiffness k?


(ii) What is the energy minimum C?


(c) Find the resonance frequency of a copper atom in a linear chain of atoms? [Assume only nearest neighbor interactions]


(d) Find the vibration amplitude at the temperature T = 5⁰C. Assume that the oscillator has one degree of freedom.

[ Use k_B = 1.38⨯10^-23 J/K/atom as Boltzmann's constant. ]

1. A box of mass 5kg moves to the left at a speed of 6m/s. The box is moving toward an unstretched spring of spring constant 500N/m that is attached to a barrier. If the floor is frictionless, how much does the spring compress in bringing the box to rest? If instead the floor has a coefficient of friction of 0.4, how much does the spring compress in bringing the box to rest?

Determine the magnitude of the gravitational force Mars would exert on man if he was on the surface of Mars. The mass of the man is 67.0kg . The mass of the Mars is 6.42

1. Explain the difference between linear, radial, and angular acceleration and identify which "G" force vector is most significant in normal aircraft flight.

Prelab 7: DC Circuits 1

What are the units of Resistance?

Watch the video tutorial about series and parallel circuits. Explain what ammeters and voltmeters do – Why are they hooked up to the circuit differently, and why don't they affect the circuit?

What is the resistance of a resistor when the colored bands read yellow, red, green and gold ?

What is a thermistor?

Three resistors with values of 1,488 Ohms, 1,101 Ohms and 860 Ohms are in parallel with each other in a circuit. What is the equivalent resistance of this parallel circuit?

<1>

An automobile of mass 1500kg moving at 25m/s collides with a truck of mass 4500kg at rest. This time, the car and the truck bounce off each other completely elastically. What is the final velocity of the truck after the collision? Call the direction of the automobile before the collision positive.

<2>

An automobile of mass 1500kg moving at 25m/s collides with a truck of mass 4500kg at rest. This time, the car and the truck bounce off each other completely elastically. What is the final velocity of the car after the collision? Call the initial direction of the automobile positive.

A block slides down a frictionless inclined ramp. If the ramp angle is 26° and its length is 29 m, find the speed of the block as it reaches the bottom of the ramp, assuming it started sliding from rest at the top.

A thin, rectangular sheet of metal has mass M and sides of length a and b. Find the moment of inertia of this sheet about an axis that lies in the plane of the plate, passes through the center of the plate, and is parallel to the side with length b. Express your answer in terms of some or all of the variables M, a, and b

Find the moment of inertia of the plate for an axis that lies in the plane of the plate, passes through the center of the plate, and is perpendicular to the axis in part A.

Express your answer in terms of some or all of the variables M, a, and b.

If matter has a wave nature, why is this wave-like characteristic not observable in our daily experiences?

Any object of macroscopic size—including a grain of dust—has an undetectably small wavelength, so any diffraction effects it might exhibit are very small, effectively undetectable. Recall historically how the diffraction of sound waves was at one time well known, but the diffraction of light was not.

Only objects of macroscopic size, like an ocean wave, actually exhibit a wave nature. Smaller, microscopic objects—including a grain of dust—do not exhibit a wave nature.    

Only objects of microscopic size, like an atom, actually exhibit a wave nature. Larger, macroscopic objects—including a grain of dust—do not exhibit a wave nature.

Any object of macroscopic size—including a grain of dust—has a large wavelength, so any diffraction effects it might exhibit are very large, too large to be detectable. Recall historically how the diffraction of sound waves was at one time well known, but the diffraction of light was not.

Part 1. A certain helix in three-dimensional space is described by the equations x = cos theta, y = sin theta, and z = theta. Calculate the line integral, along one loop of this helix, of the dot product V

An LED that emits light of wavelength λ = 614 nm illuminates the phototube. A reverse bias is applied to the phototube (a voltage that opposes the current flow). This is adjusted carefully until the photocurrent drops to zero. The stopping potential is found to be Vo = 0.162 V.

The LED can now be changed and the process repeated for a different λ. Then the data can be plotted to determine Planck's constant, h.

For the data collected above what value would you plot on the x-axis of your graph? (Use c = 3.00 x 108m/s.)

Express your answer in SI units to 3 significant figures.

Entering numbers in scientific notation: Example: 1.45 x 10-9 should be entered as 1.45E-9

%3Cp%3ECan%20someone%26nbsp%3Bplease%26nbsp%3Bexplain%26nbsp%3Bthis%26nbsp%3Bto%26nbsp%3Bme%3F%26nbsp%3BI'm%26nbsp%3Busing%26nbsp%3Bthe%26nbsp%3Bequation%26nbsp%3Bx-x(naught)%3DV(naught)%26nbsp%3Bt%26nbsp%3B%2B%26nbsp%3B1%2F2%26nbsp%3Bat%5E2%2C%26nbsp%3Bbut%26nbsp%3BI%26nbsp%3Bam%26nbsp%3Bnot%26nbsp%3Bgetting%26nbsp%3Bthe%26nbsp%3Bright%26nbsp%3Ba%3Cspan%26nbsp%3Bstyle%3D%22background-color%3A%26nbsp%3Brgb(255%2C%26nbsp%3B255%2C%26nbsp%3B255)%3B%22%3Enswer.%26nbsp%3B%3Cspan%26nbsp%3Bstyle%3D%22font-family%3A%26nbsp%3Barial%2C%26nbsp%3Bverdana%2C%26nbsp%3Bgeneva%2C%26nbsp%3Blucida%2C%26nbsp%3B'lucida%26nbsp%3Bgrande'%2C%26nbsp%3Barial%2C%26nbsp%3Bhelvetica%2C%26nbsp%3Bsans-serif%3B%26nbsp%3Bfont-size%3A%26nbsp%3B13px%3B%22%26nbsp%3Bdata-mce-style%3D%22font-family%3A%26nbsp%3Barial%2C%26nbsp%3Bverdana%2C%26nbsp%3Bgeneva%2C%26nbsp%3Blucida%2C%26nbsp%3B'lucida%26nbsp%3Bgrande'%2C%26nbsp%3Barial%2C%26nbsp%3Bhelvetica%2C%26nbsp%3Bsans-serif%3B%26nbsp%3Bfont-size%3A%26nbsp%3B13px%3B%22%3EFor%26nbsp%3Bpart%26nbsp%3BB%26nbsp%3BI%26nbsp%3Blet%26nbsp%3Bt%3Dsqrt(2h%2Fg).%26nbsp%3BBut%26nbsp%3BI%26nbsp%3Bhave%26nbsp%3Bno%26nbsp%3Bidea%26nbsp%3Bwhat%26nbsp%3BI%26nbsp%3Bam%26nbsp%3Bdoing.%26nbsp%3BCan%26nbsp%3Bsomeone%26nbsp%3Bexplain%26nbsp%3Bthis%26nbsp%3Bwith%26nbsp%3Bnotes%3F%3C%2Fspan%3E%3C%2Fspan%3E%3C%2Fp%3E%3Cp%3E%3Cimg%26nbsp%3Bclass%3D%22user-upload%22%26nbsp%3Bsrc%3D%22http%3A%2F%2Fmedia.cheggcdn.com%2Fmedia%252Fa86%252Fa86bb10d-6ca4-4ec9-80c6-432c34427566%252Fphpw1kCCc.png%22%26nbsp%3Bheight%3D%22410%22%26nbsp%3Bwidth%3D%22860%22%26nbsp%3Bdata-mce-src%3D%22http%3A%2F%2Fmedia.cheggcdn.com%2Fmedia%252Fa86%252Fa86bb10d-6ca4-4ec9-80c6-432c34427566%252Fphpw1kCCc.png%22%3E%3C%2Fp%3E

A wheel has an initial angular velocity of 1 rad/s and undergoes an angular acceleration of 10 rad/s^2. (a) How many radians does it rotate in 4 sec? (b) What is its angular velocity at this time?

An alpha particle with kinetic energy 12.0 MeV makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude L=p0b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.30×10⁻¹² m . (Assume that the lead nucleus remains stationary and that it may be treated as a point charge. The atomic number of lead is 82. The alpha particle is a helium nucleus, with atomic number 2.)

Part A

What is the distance of closest approach?

Part B

Repeat for b=1.50×10⁻¹³ m .

Part C

Repeat for b=1.30×10⁻¹⁴ m .