A wall consists of 3 cm of exterior wood and 2 cm of interior wood separated by a 15 cm layer of polystyrene foam. If the interior is kept at 19 °C, calculate the outside temperature for which the heat loss through the wall is 10 W/m2.

what does the structure of our galaxy tell us about how our galaxy formed?

The drawing shows an ideal gas confined to a cylinder by a massless piston that is attached to an ideal spring. Outside the cylinder is a vacuum. The cross-sectional area of the piston is A = 2.50 × 10-3 m2. The initial pressure, volume, and temperature of the gas are, respectively, P0, V0 = 6.00 × 10-4 m3 and T0 = 273 K, and the spring is initially stretched by an amount x0 = 0.092 m with respect to its unstrained length. The gas is heated, so that its final pressure, volume, and temperature are Pf, Vf and Tf and the spring is stretched by an amount xf = 0.14 m with respect to its unstrained length. What is the final temperature of the gas?

1) In softball, the pitcher throws underhand with the arm fully extended (straight at the elbow). In a fast pitch the ball, of mass m = 0.156 kg, leaves the hand at a speed of 139 km/h, when the arm is pointed vertically downward.

A) Find the rotational kinetic energy, in joules, of the pitcher’s arm-ball system, given that the arm's moment of inertia is 0.725 kg⋅m² and the ball leaves the hand at a distance of 0.625 m from the pivot.

B) What force, in newtons, do the muscles exert to cause the arm to rotate, assuming the force is constant and its effective perpendicular lever arm is 3.2 cm? Assume also that the pitcher's arm starts extended horizontally behind her at rest and the ball is released at the bottom of the swing, as described in part (a). Approximate the arm as a uniform rod.

2. Zorch, an archenemy of Superman, decides to slow Earth’s rotation to once per 29.5 h by exerting a force parallel to the equator, opposing the rotation. He uses an old Saturn V rocket, stolen from NASA, which was originally used to send astronauts to the Moon. This rocket can exert a thrust of F = 3.85 × 10⁷ N.

A)  If the original angular velocity of Earth is ω₀ and Zorch is trying to get the Earth to an angular velocity of ω, how much time will it take him? Use M and R for the mass and radius of the Earth.

B)How long, in seconds, will it take him to do this? (Notice that this period gives Superman time to devote to thwarting other villains.)

Can someone please explain the Carnot Cycle graph in terms of what equations to use and the concepts.

This is what I think but I keep getting mixed up:

Path A to B which is Reversible Isothermal Expansion, Delta U= 0, and according to first law Q= -W and we use RTln V2/V1 for W?  In path B to C, the gas expand Adiabatically, so Q= 0 and Delta U= - W. Since it is expansion so the work will be negative. We use the formula W= - Cv (T2-T1) for this path. For Path C to D, it is isothermal compression so do we flip the equation to W= RTln V4/V3 or we can keep it V3/V4 but put the negative sign on it so like - RTlnv3/v4. Finally, for path D to A, it is an adiabatic Compression do we use W= Cv(t2-t1)?

A 0.140 kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.720 m/s. It has a head-on collision with a 0.302 kg glider that is moving to the left with a speed of 2.13 m/s. Suppose the collision is elastic.

a) Find the magnitude of the final velocity of the 0.140 kg glider. Express your answer in meters per second.

b) Find the direction of the final velocity of the 0.140 kg glider.

c) Find the magnitude of the final velocity of the 0.302 kg glider. Express your answer in meters per second.

d) Find the direction of the final velocity of the 0.302 kg glider.

Describe how the motion of a planet (like Mars) among the stars of the zodiac on the sky is qualitatively different from the motion of an object like our Sun among the stars of the zodiac.

Describe the two hypotheses as to the origin or reason for the Sun’s motion relative to the stars of the Zodiac, first the self-centered view then the more modern less self- centered hypothesis.

A gun is used to shoot a target located at a distance of 100.0m. The gun is pointed horizontally at a height of 1.3 m above the ground. At the impact with the target, 78% of the kinetic energy of the bullet is absorbed by the target, and all vertical velocity is lost. The bullet rebounds hitting the shooter in the knee (between 50.0 and 50.2 cm above the ground). Calculate the initial velocity of the bullet with a 0.1 m/s precision. Neglect air resistance. The mass of the bullet is 4.2 g.

Please when solving write out the equations before using them.

In detecting the direction of a sound source, what factors are most important at (a) low frequencies and (b) high frequencies? With reference to the structure of the human head, why is discrimination of a sound source less accurate at frequencies close to 2000 Hz? What directions are particularly difficult to determine? Why?

PLEASE DO NOT REPOST AN OLDER ANSWER, THEY ARE NOT RIGHT

Say our goal is to diffuse a gas into a liquid. What must we do to temperature and why to increase diffusion?

Do you have any examples of where we experience diffusion (affected by temperature) in the environment?

I did an experiment in which a cart on wheels is getting pulled by a pulley hanging off the surface. The pulley has a 50g hanger which causes the motion. The cart is 300g and then in different trials added one 50g weight, two, three, and then four. The slope was 0 degrees. My question is: Describe (and show with pictures) what forces change for each of the different configurations used.

A pendulum swings through an arc of 90.0° (45.0° on either side of the vertical). The mass of the bob is 2.90 kg and the length of the suspending cord is 2.25 m. (a) Find the tension in the cord at the end points of the swing. (b) Find the velocity of the bob as it passes its lowest point and the tension in the cord at this point

In areas of enhanced heat flow, geothermal heating can be used to supply heating to homes, either by using ground water directly or by placing a water reservoir at depth. In Iceland, where the average temperature over the year is 6.1ºC, the geothermal flux can be as high as 300 mW m-2.

(a) If you wanted to be able to supply a home with water at a temperature of 50ºC, how deep would your reservoir need to be?

(b) Why might Iceland have such a high geothermal flux compared to other areas?

An object 5 centimeters high is placed 15 cm in front of a converging lens with focal length 5 cm. Using graph paper (turn the paper so that the long side is horizontal) and a straight edge, draw appropriate rays to locate the image. Chose a scale (tell me what it is!) such that the lens is in the center of the page and the object is near the left side of the page a. Is the image real or imaginary? Explain your conclusion b. What is the height of the image? c. Where is the image located? d. What is the ratio (image height)/(object height)? e. Compare your results with those predicted by the lens equation 1/f = 1/p + 1/q