An insulated wall consists of an exterior wood layer of thickness 3.1 cm and an interior layer of foam insulation of thickness 2.3 cm . For the wood, k=0.080W/(m⋅K), and for the foam insulation k= 0.010 W/(m⋅K). The outer surface of the wood is at a constant -15.0 ∘C , and the inner surface of the foam insulation is at a constant 19.0 ∘C .

Calculate the temperature in Celsius where the wood and foam insulation are in contact. T=???

Calculate the heat flow per unit area through the two-layer wall. H=?? W/m^2

When t = 0, the position of a point is s= 6m, and its velocity is v= 2m/s. From t = 0 to t= 6s, the acceleration of the point is a = 2+ 2t² m/s² .From t = 6s until it comes to rest, its acceleration is a = -4m/s²

^{a.) What is the total time of travel?}

^{b.) What total distance does the point move?}

A uniform cubical crate is 0.575 m on each side and weighs 900 N. It rests on the floor with one edge against a very small, fixed obstruction. At what height above the floor must a horizontal force of 625.0 N be applied to the crate to just tip it?

Two rectangular pieces of plane glass are laid one upon the other on a table. A thin strip of paper is placed between them at one edge, so that a very thin wedge of air is formed. The plates are illuminated at normal incidence by 542nm light from a mercury-vapor lamp. Interference fringes are formed, with 14.0fringes/centimeter .

Find the angle of the wedge.

A spacecraft with a proper length of 350 m passes by an observer on the Earth. According to this observer, it takes 0.780 µs for the spacecraft to pass a fixed point. Determine the speed of the spacecraft as measured by the Earth-based observer.

Please show how you arrive at your answer!

Explain the following natural events in terms of the laws of physics that you have learned in this class. Include figures if necessary. Answer any two.

How does a bird fly?

If you keep boiled egg inside refrigerator, it becomes difficult to take the shell off. But if you keep it warm water for a minute or so it becomes very easy. Why?

Why inside swimming pool we feel very light weight?

Mention all the laws of physics applied in these processes.

Explain the following natural events in terms of the laws of physics that you have learned in this class. Include figures if necessary. Answer any two.

How does a bird fly?

If you keep boiled egg inside refrigerator, it becomes difficult to take the shell off. But if you keep it warm water for a minute or so it becomes very easy. Why?

Why inside swimming pool we feel very light weight?

Mention all the laws of physics applied in these processes.

(a) Using Kirchhoff’s laws, derive an equation for the voltages, V1 and V2, across two resistors, R1 and R2, in series connected to a voltage supply V .

(b) Using Kirchhoff’s laws, derive an equation for the voltages across two resistors R1 and R2 in parallel connected to a voltage supply V .

1- relate characteristics of semiconductor basic mechanism of electrical conduction

2- determine important parameters of semiconductor

3- describe operation principle of semiconductor devices

4- demonstrate the understanding of intrinsic-extrinsic semiconductor characteristic`.

A picture window has dimensions of 1.40 m

A 120-pF capacitor and a 480-pF capacitor are both charged to 3.10 kV. They are then disconnected from the voltage source and are connected together, positive plate to negative plate and negative plate to positive plate.

(a) Find the resulting potential difference across each capacitor.

(b) Find the energy lost when the connections are made.
µJ

A 45 kg figure skater is spinning on the toes of her skates at 0.50 rev/s . Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg , 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 62 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head, where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall cylinder. Part A What is her new rotation frequency, in revolutions per second? Express your answer to two significant figures and include the appropriate units.

What is her new rotation frequency, in revolutions per second?

A spherical bowling ball with mass m = 3.3 kg and radius R = 0.11 m is thrown down the lane with an initial speed of v = 8.9 m/s. The coefficient of kinetic friction between the sliding ball and the ground is ? = 0.28. Once the ball begins to roll without slipping it moves with a constant velocity down the lane.

What is the magnitude of the angular acceleration of the bowling ball as it slides down the lane?

What is magnitude of the linear acceleration of the bowling ball as it slides down the lane?

How long does it take the bowling ball to begin rolling without slipping?

How far does the bowling ball slide before it begins to roll without slipping?

What is the magnitude of the final velocity?

Current passes through a solution of sodium chloride. In 1.00 second, 2.68