1. Which of the following would not be observed if you observed the sky without a telescope? (More than one answer can be correct).

Venus moves relative to the Sun.

Mars moves relative to the stars.

The starts rotate about a single point in the sky.

The stars move relative to each other.

The Moon moves relative to the stars.

2.Comparing theories by Ptolemy and by Copernicus. (More than one answer may be correct)

A ball of mass m is attached to a string of length L. It is swung in a vertical circle with enough speed to keep the string taut throughout the motion. Assume the ball travels freely in the circle with negligible loss of mechanical energy. Determine if the following six statements are true or false; e.g., enter TTFFFF.

1. 
   
2. The tension in the string is less at the top of the circle than at the bottom of the circle.
3. The acceleration of the ball at the bottom of the circle is directed `down'.
4. mv_b²/L = T_b−mg, where v_b and T_b are the speed of the ball and the tension of the string at the bottom of the circle.
5. The speed of the ball at the bottom of the circle is greater than the speed at the top of the circle.
6. The tensions at the top and at the bottom of the circle depend on the average speed of the ball.
7. The tension in the string at the top of the circle is always greater than the weight of the ball.

If I want to design an experiment related to kinetic friction, can the following proposal meet the requirement?
By varying the weight of an object and measure the stopping distance of that object.
Is this related to kinetic friction? If not, how should I change my experiment?

A cylindrical air tank has dimensions diameter = 0.2m and height 0.8m. an attached pressure gage reads 200 kPa and the temperature is 27 celcius. an electrical heater is energized inside and it raises the temperature to 147 celius in 2 minutes. Calculate the mass of air in the tank (kg) (have to use ideal gas law, molecular weight of air)

n = 4.33 mol of Hydrogen gas is initially at T = 378 K temperature and pi = 2.88

A 4.50 kg solid cylinder with radius 10.0 cm is allowed to roll down a uniform slope that has been inclined at 22°. The cylinder is stationary at the top and the length of the incline is 5.50 meters.

1. What percentage of the total KE is rotational KE at the bottom of the ramp?

2. What is the angular acceleration of the cylinder as it rolls down the ramp?

3. Find the velocity of the cylinder at the bottom of the ramp.

4. What is the net torque applied to the rolling cylinder during its motion down the ramp?

A 1,300-N crate is being pushed across a level floor at a constant speed by a force F of 390 N at an angle of 20.0° below the horizontal, as shown in the figure a below. Two figures show a side view of a crate positioned upon a horizontal surface. Figure (a): An arrow pointing downward and to the right is labeled vector F and forms an angle of 20° below the horizontal as it approaches the upper left edge of the crate. Figure (b): An arrow pointing upward and to the right is labeled vector F and forms an angle of 20° above the horizontal as it extends from the upper right edge of the crate.

(a) What is the coefficient of kinetic friction between the crate and the floor? (Enter your answer to at least three decimal places.)

0.256 Correct: Your answer is correct.

(b) If the 390-N force is instead pulling the block at an angle of 20.0° above the horizontal, as shown in the figure b, what will be the acceleration of the crate? Assume that the coefficient of friction is the same as that found in part (a).

0.7 Incorrect: Your answer is incorrect.

6. Given the Earth's albedo of A = 0.3, what surface temperature do you predict at equilibrium? Is this consistent with the Earth's actual average temperature of 14C? How do you explain the discrepancy?

A 1094 kg van, stopped at a traffic light, is hit directly in the rear by a 727 kg car traveling with a velocity of +2.41 m/s. Assume that the transmission of the van is in neutral, the brakes are not being applied, and the collision is elastic. What is the final velocity of the car?

Two semi-infinite grounded conducting planes intersect at 60 degrees. A point charge is situated inside this wedge-shaped region.
(a) Find image charges to obtain the potential between the conductors.
(b) Can you use the result of part (a) to obtain the Green function for the Dirichlet problem between the planes? No explicit calculation is required; just explain

1. A large, two-story office building has a first floor which measures 500 ft by 750 ft and a second story which is 500 ft by 500 ft. This building used 76,650 GWh of electricity last year and 120,035 therms of natural gas.

   1. a) What is the EUI of the building? How does this compare to similar buildings?

   2. b) Currently the office encourages carpooling and public transportation and therefore does not have a parking structure attached. They are considering adding this as an amenity to their employees. How does an unheated, 145,000 square feet parking garage change the EUI? How might this

      impact an energy audit of the building?

   3. c) By 2025, the company would like to add solar panels on the roof of the building to create on-site

      electricity. These panels are projected to create a minimum of 20,000 kWh, annually. What is thebuilding’s new EUI?

testing a scientific hypothesis involves four main steps. examine each of these steps in detail.

An accelerator in an automobile is defined as anything a person directly
interacts with, resulting in a change in motion of the vehicle. Your mission is to list at least 12
accelerators that you would find in any standard automobile. You must accurately describe
each accelerator and state the external force that the accelerator indirectly affects. You
should also show the external forces that directly cause each acceleration using adequate
diagrams and explanation. Please, only consider standard cars or trucks; the Batmobile,
monster trucks, or even police vehicles are not standard automobiles.

A spring that has a force constant of 1050 N/m is mounted vertically on the ground. A block of mass 1.40 kg is dropped from rest from height of 1.40 m above the free end of the spring. By what distance does the spring compress?