Solar energy is an alternative to fossil fuels for providing electrical power for both homes and businesses. It may be locally produced and used at the same location as the panels, which reduces distribution costs. Large facilities may be located in available space and the power added to the "grid" that distributes electricity. Solar power may be a better choice in rural or undeveloped areas where the grid infrastructure is unreliable or just not there, and it has been discussed as an alternative for reconstruction in storm-damaged Puerto Rico. It is also useful in less sunny areas, and here in Kentucky the regional power provider is developing a shared solar energy farm to supplement its conventional power plants. Even the Coal Museum in eastern Kentucky has solar panels to provide building power.

1. The Sun provides approximately 1.4 kilowatts (kW) of energy adding all the light striking one square meter perpendicular to a line to the Sun above the Earth's atmosphere. If solar panels are 25% efficient in converting this optical energy to electrical energy, and if they are oriented to make maximum use of incident sunlight, how much panel area is needed to develop 10% of the regional power production which is 3.5 gigawatts (GW) while the Sun shines? (3.5 GW is 3,500 MW. Currently LG&E has a 10 MW solar farm covering 50 acres.)

2. A typical single solar panel that would be installed on a home uses crystalline silicon as the material that creates the current, measures 1x2 meters, and produces 340 watts at 48 volts. It is said to be 17% efficient, allowing that not all the sunlight at the top of the atmosphere reaches the surface, and that some wavelengths are beyond the range over which silicon responds. How many of these panels would be needed to supply 15 kW that would fulfill the peak needs of a typical home? What area of the roof would they cover? This is for peak use, but typically the average power needs are about 5 kW.

3. If it is sunny 8 hours a day, then you would need 3X as many panels and a way to store energy to use them 24/7, but storage also allows you have fewer panels to meet peak needs. Allowing that the panels gather enough energy during 8 hours to provide power for that time and for 16 more hours, how much energy has to be stored? Consider two alternatives: pumped water and Tesla batteries. If you could pump water to a height of 20 meters, say to a pond or pool up the hill from your home, how much water by volume would have to be moved to store this energy . (Use the potential energy of gravity, mgh, to figure this out. ) For batteries, consider the Tesla "Powerwall", a module that stores 13.5 kWh of energy and provides 7 kW peak AC power.

4. Given what you know about the physics of solar, comment on the viability of it as a sole source of power for your home, and your rechargeable electric car. If you have a clever way of storing energy, mention it here too.

14. Explain the Coriolis effect. Where does the factor of 2 in the mathematical formulation of the Coriolis force come from?

Astrophysics

How do we know which one of the two energy transport equations to use?

Three charge particles are shown in the figure below, Q₁=-11 nC (-3.50cm,0), Q₂=3 nC (0,0) andQ₃=7 nC (1.50cm, 0).

all at x axis

A) Find the magnitude of net force acting on Q₁ . What is the direction of this net force?

B) Find the magnitude of net force acting on Q₃. What is the direction of this net force?

Question 4. BONUS 20pts. Now relax and think about all studied topics in the General Physics course. You are asked to define 10 different " The right-hand rule". Here you first define the application and explain how the right-hand rule is applied to find the direction of physical concept. This is a free question that we expect independent study. DO NOT GET A COPY OF YOUR FRIENDS DEFINITION. OPEN THE BOOK AND FIND 10 DIFFERENT APPLICATION OF THE RULE. To get full credit, you must give a full answer as asked above. Give answers in Good English

Problem 5.135 An insulated 0.15-m3 tank contains helium at 3 MPa and 130°C. A valve is now opened, allowing some helium to escape. The valve is closed when one-half of the initial mass has escaped. Determine the final temperature and pressure in the tank.

You have a lightweight spring whose unstretched length is 4.0 cm. First, you attach one end of the spring to the ceiling and hang a 1.4 g mass from it. This stretches the spring to a length of 5.2 cm . You then attach two small plastic beads to the opposite ends of the spring, lay the spring on a frictionless table, and give each plastic bead the same charge. This stretches the spring to a length of 4.8 cm . What is the magnitude of the charge (in nCnC) on each bead?

a 100 kg student is compressed 50 cm on a spring with a spring constant of k = 80,000 N/m. He is on top of a 10 m frictionless hill. He then is released from rest. He goes down to the bottom of the hill before sliding up a 30° frictionless hill. a. (8 pts) Find the speed of the student when he reaches the bottom of the hill. b. (9 pts) Find the distance D the student travels up the hill before momentarily stopping. Use whichever method you wish.

You go out to the barn and start up the egg collecting machine. Eggs slide down a 30 degree ramp with a coefficient of kinetic friction of 0.2. What is the acceleration of the egg as it moves down the ramp?

If the ramp is two meters long, how fast are the eggs moving when they hit the bottom?

If we assume that the eggs are spherical with a radius of 3 cm, mass 200 grams and roll down the ramp instead of sliding, now recalculate how fast they are moving when they reach the bottom.

Charlie kicks a soccer ball up a small incline. On the way up, ball’s acceleration has magnitude |a| = 0.45 m/s2 and is directed in downhill direction. Charlie kicks the ball at the bottom of the incline and then immediately start to walk up the incline with constant speed. Charlie performs twi different trials. a) In the first trial, Charlie kicks the ball with initial speed v0 = 3.4 m/s. Charlie is 2.3-m behind the ball when the ball is at the highest point. What is the speed vC of Charlie? b) Charlie performs the second trial. He kicks the ball with unknown speed v 0 0 but walks with the same speed vC as in the first trial. Charlie is now 0.8 m behind the ball when the ball is at the highest point. What is the initial speed v 0 0 of the ball at the bottom of the hill? (Hint: You need to set-up a quadratic equation for v 0 0 ).

In the figure, block 1 of mass m1 slides from rest along a frictionless ramp from height h = 3.3 m and then collides with stationary block 2, which has mass m2 = 5m1. After the collision, block 2 slides into a region where the coefficient of kinetic friction μk is 0.2 and comes to a stop in distance d within that region. What is the value of distance d if the collision is (a) elastic and (b) completely inelastic?

Two charged droplets of toner ink behave as two shells of uniform surface charge density. (Toner is an insulating material, not conductive.) The two drops have total charge qi, radiusRi, and centre positionri,i= 1,2. Assuming the drops do not overlap, derive the electric potential, V(r), everywhere inside and outside the spheres. Is the voltage (potential) inside shell 1 constant?

Two parts:

a) An object with an initial mass m_i=7and an initial velocity v_i=6m/s making an angle of 40 degrees with the +x axis has, after a time 4 seconds, final velocity v_f=3making an angle of 0 degrees wrt -x. a) Determine the net force acting on the mass corresponding to F_net=(p_f-p_i)/delta(t), needed to produce that change in momentum. b) Now, assuming there is gravity plus a second, contact force acting on the mass, estimate the magnitude of the second contact force applied to the mass over the time t seconds (using F(contact) + F(gravity) = F(net)) and draw the vectors demonstrating graphical addition.

b) An 6 kg mass, moving at an angle of 40 degrees wrt the +x axis with an initial velocity magnitude |5| collides inelastically with an 8 kg mass, moving at an angle of 50 degrees wrt the +x axis and with an initial velocity magnitude v_{1= 3m/s}. Determine a) the angle that the composite object makes with the axis of your choice, b) the magnitude of the final velocity of the single object, as well as c) the heat generated in the collision.

Pure stoichiometric ZnO is heated to 1400 K in an evacuated chamber of a vapor deposition furnace. What is the partial pressure of Zn and O2 generated by the thermal decomposition of ZnO Information you may find useful AC no at 1400K = -183 kJ/mol

Question 6

a. If the contact angle of a liquid with its container walls is 90° what can we say about the different forces involved and what are those forces? Include a discussion of the meniscus in this case. [3 marks]

b. Explain why the pressure inside a bubble is larger than the pressure surrounding the bubble. [2 marks]
c. At the top of a ski lift a 1 tonne concrete block counterweight is supported by a 10 m long steel cable (of 16 mm diameter when not under stress). You must include the mass of the cable when answering the following questions. The density of steel is 8000 kg m-3, the tensile strength of steel is 5.0 x 108 Pa, the Elastic Modulus of steel is 2.1 x 1011 Pa and Poisson’s ratio for steel is 0.28.
i. What is the safety factor of the system? Comment on your answer. [6 marks]
ii. What is the change in diameter of the cable when supporting the counterweight? [3 marks]
iii. What energy is stored in the cable when supporting the counterweight? [2 marks]
iv. Calculate the Bulk and Shear moduli of steel. [4 marks]