Tell me about the formula and principle of obtaining the focal length and size of the Zoom lens with one convex lens and two concave lenses.

Using complete sentences and the concepts discussed in Chapter 15 and 16 (including the type of heat transfer, frequency, wavelength, and energy) describe the greenhouse effect, and how it determines the temperature of Earth (or enclosed objects)

Describe a way to produce energy that causes no environment harm

1.

You throw a 50kg ball upwards at 25m/s. The ball strikes the beginning of the spring when it's 8 meters in the air, then it begins to compress the spring. How far did the spring compress? The spring constant is 300 Newton/meter.

Also, if the spring was not there, how far would have it gone up (set the final velocity to zero)?

2.

You see a teeter-todder again. It's horizontal (balanced). A 100kg person sits 4 meters to the right, and a 30kg person sits 8 meters to the left (of the pivot). On what side, and where, must a 69kg person sit for it to balance? And what force must the ground push up on the tetter-todder, in order for it to not fall down (find the ground's normal force)?

Starting from rest, a truck travels in a straight line for 7.0 s with a uniform acceleration of +1.6 m/s2. The driver then applies the brakes for 3.0 s, causing a uniform acceleration of −2.0 m/s2 over that time. (a) What is the truck's speed at the end of the braking period? (b) What is the total distance traveled by the truck (from the point where it started at rest to the end of the braking period)

Relative humidity isn't everything. Why is it that outdoor air of 80 Fo at 55% humidity will feel more “muggy” than a 50 Fo cave at 75% humidity? What other parameter is a better measure of the actual amount of moisture in the air, and how do we define it? Then give two examples of when keeping close track of moisture in the air is important.

i want to ask about underwater applications of lifi.as we know that that that light caannot travel much in water it is used for short range communications then what should be these short range applications.another question is that why visible light cannot cross the walls but radio waves do?

You have a glass ball with a radius of 2.00 mm and a density of 2500 kg/m3. You hold the ball so it is fully submerged, just below the surface, in a tall cylinder full of glycerin, and then release the ball from rest. Take the viscosity of glycerin to be 1.5 Pa s and the density of glycerin to be 1250 kg/m3. Use g = 10 N/kg = 10 m/s2. Also, note that the drag force on a ball moving through a fluid is:

Fdrag = 6πηrv .

(a) Note that initially the ball is at rest. Sketch (to scale) the free-body diagram of the ball just after it is released, while its velocity is negligible.

(b) Calculate the magnitude of the ball’s initial acceleration.

(c) Eventually, the ball reaches a terminal (constant) velocity. Sketch (to scale) the free-body diagram of the ball when it is moving at its terminal velocity.

(d) Calculate the magnitude of the terminal velocity.

(e) What is the magnitude of the ball’s acceleration, when the ball reaches terminal velocity?

(f) Let’s say that the force of gravity acting on the ball is 4F, directed down. We can then express all the forces in terms of F. (For instance, you might label a force on a free-body diagram as “Fdrag = 3F”.) Sketch three free-body diagrams, and express all forces in terms of F. Hint: do the middle one last.

Initial FBD FBD for when v = half FBD for when (when released from rest) the terminal velocity v = terminal velocity

(g) How does the net force in the left-most free-body diagram compare to that in the middle free-body diagram? Combine that information with your result from problem 1, regarding the initial acceleration, to find the magnitude of the acceleration when the ball’s speed is half the terminal speed.

(h) Take down to be positive for all your graphs. (i) Sketch a grapch of the ball’s acceleration as a function of time; (ii) sketch a graph of the ball’s velocity as a function of time; (iii) sketch a graph of the ball’s position as a function of time. If you can be quantitative with your axis labels, then do so.

A 50-g cube of ice, initially at 0.0°C, is dropped into 200 g of water in an 80-g aluminum container, both
initially at 30°C. What is the final equilibrium temperature? (Specific heat for aluminum is 900 J/kg×°C,
the specific heat of water is 4 186 J/kg×°C, and Lf = 3.33 ´ 105 J/kg.)

Touching hot objects is painful due to the high-velocity impacts of many, many atoms. Touching extremely cold objects can sometimes be painful as well. If the atoms/molecules in a cold object are moving very slowly, what causes the painful sensation?

An ideal gas undergoes the following Carnot Cycle. It starts in a chamber of volume .0065 m³ and temperature 345 Kelvin and pressure 630 kPa (state 1). It is allowed to expand isothermally to a volume of .01066 m³ (state 2) while heat is added to the gas.  Then it expands adiabatically to a volume of .01784 m³ (state 3). Then, it is compressed isothermally to a volume of V_f m³ (state 4) while heat is extracted from the gas.  Finally, it returns to its initial state in an adiabatic process.  (The gamma of the gas, γ = 1.28,  C_v = 3.5R).

How much heat is added in the 1^st isothermal process and the efficiency of this engine?

a.)1.878 kJ, 11.2%

b.) 2.029 kJ, 11.2%

c.) 2.029 kJ, 13.6%

d.) 2.334 kJ, 13.6%

e.) 2.334 kJ, 15.8%

Consider the retarded scalar and vector potentials. Show that they satisfy the Lorentz gauge.

A flaggpole of mass 5km and length 3.0 m is hinged at a wall and supported by a horizontal position by a cable affected to the flagpole at 2.0 M from the wait. The cable makes an angle of 25 with the horizontal. An iron plate of mass 1.5 kg is hanged at the free end of the flagpole.

A. what is the tension in the cable.

B. What is the horizontal force excerted on the hinge of the wall.

C. What is the vertical force excerted on the hinge at the wall. Use (+) or (-) to indicate direction