If the coefficient of static friction is 0.60, and the same ladder makes a 46° angle with respect to the horizontal, how far along the length of the ladder can a 55.0-kg person climb before the ladder begins to slip? The ladder is 7.5 m in length and has a mass of 21 kg.

A 621-kg elevator starts from rest and moves upward for 3.20 s with constant acceleration until it reaches its cruising speed, 1.65 m/s.

(a) What is the average power of the elevator motor during this period?
hp

(b) How does this amount of power compare with its power during an upward trip with constant speed? (Give the power during an upward trip with constant speed.)
hp

A 1,000-kg car moving east at 90 km/h collides head-on with a 1,500-kg car moving west at 50 km/h, and the two cars stick together. (a) Which way does the wreckage move and with what initial speed? (b) How much KE is lost in the collision?

A soap bubble is 95 nm thick and illuminated by white light incident perpendicular to its surface.

The longest wavelength in nm which is constructively reflected, assuming soap has the same index of refraction as water (n = 1.33) is equal to 505.4 nm.

Draw a diagram of the mediums showing where, if any, a phase change occurs.

State whether you are looking for constructive of destructive interference.

Your younger brother is supposed to mow the lawn using a push mower. He reasons from Newton's third Law that the mower will push back with the same force he exerts on the mower; therefore nothing will move and attempting to mow the lawn is pointless. What is wrong with his reasoning?

Consider our graphical analysis of the bound states in a finite square well of depth V₀ and width a. Determine

a) The condition on V₀ and a that there is at most one bound state in the problem.

b) The condition on V₀ and a that there is at most four bound states in the problem.

c) Suppose the potential parameters are such that the third bound state is just barely bound. What can you say about the binding energy of the first and second bound states?

Construct the explicit form of the lowest three eigenfunctions of the harmonic oscillator.

Say the density of air is 1.23 kg/m3 and the density of helium is 0.164 kg/m3 when both are at STP. Let's model a balloon as a sphere of radius 0.12 m, with mass 2 g.

1) What is the mass of the helium that would fill a single balloon?

2) What is the buoyant force on a single balloon?

3) What is the net force on a single balloon?

4) If we attach 0.5 m of string (properties: 800 feet weighs 1 pound), what is the net force now on the balloon?

5) How many balloons would you need to have a 1 kg kitten in equilibrium, hovering just above the ground? (assume all of the strings are vertical, this is actually another problem)

List three unique meteorological features of Superstorm Sandy

A particular beam of light, with an intensity of 440 W/m², is linearly polarized at an angle of +5.00° to the vertical. You have three polarizers, which have their transmission axes aligned as follows:

Polarizer A - the transmission axis is at +19.0° to the vertical;
Polarizer B - the transmission axis is at +72.0° to the vertical;
Polarizer C - the transmission axis is at +25.0° to the vertical.

You will select two of these polarizers, and have the light pass through one and then the other.

(a) If you want to maximize the intensity of the light emerging from the second polarizer, which two polarizers should you select, and in what order should the light pass through them?

(b) For the situation in (a), when you maximize the intensity of the light emerging from the second polarizer, what is that intensity?
___________ W/m²

(c) If, instead, you want to minimize the intensity of the light emerging from the second polarizer, which two polarizers should you select, and in what order should the light pass through them?

(d) For the situation in (c), when you minimize the intensity of the light emerging from the second polarizer, what is that intensity?
____________ W/m²

For the remaining parts of the problem, we now replace the original polarized light by unpolarized light of the same intensity. For reference, the intensity is 440 W/m², and the three polarizers have their transmission axes aligned as follows:

Polarizer A - the transmission axis is at +19.0° to the vertical;
Polarizer B - the transmission axis is at +72.0° to the vertical;
Polarizer C - the transmission axis is at +25.0° to the vertical.

(e) If you want to maximize the intensity of the light emerging from the second polarizer, which two polarizers should you select, and in what order should the light pass through them?

(f) For the situation in (e), when you maximize the intensity of the light emerging from the second polarizer, what is that intensity?
___________ W/m²

(g) If, instead, you want to minimize the intensity of the light emerging from the second polarizer, which two polarizers should you select, and in what order should the light pass through them?

(h) For the situation in (g), when you minimize the intensity of the light emerging from the second polarizer, what is that intensity?
____________ W/m²

question about defibrillator.
. Why you apply the shock

. What is done when defibrillator

. How defibrillator work

. Then why we chose Biophasic

A plane wave of frequency 900 MHz is and trave ling along -y direction with the electric field amplitude of 300 V/m (in vacuum). The value of electric field is -300 V at t=0 and y=0. Choose a magnetic field direction and define the polarization. Write the wave equation of the electric and magnetic field..

Choose an isotope and describe its radioactive decay process and how it is used. Write a minimum of 150 words.

The velocity of a particle moving in the xy plane is given by ,v=(5t-4.5t^2)i+8.3j with in meters per second and t (> 0) in seconds. At t = 2.4 s and in unit-vector notation, what are (a) the x component and (b) the y component of the acceleration? (c) When (if ever) is the acceleration zero? (d) At what positive time does the speed equal 10 m/s?

A camera lens has a focal length of 100 mm (thick lens). The photographer first adjusts the location of the lens to look at an object very far away (infinite distance). Then he tries to take a picture of a person 2 meters away from the lens. How is he going to adjust (move) the lens relative to its original position? What is the distance of the adjustment?