Because Earth’s rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 62 centuries, what is the total of the daily increases in time (that is, the sum of the gain on the first day, the gain on the second day, etc.)?
An object weighs 30 N. How would you explain this statement according to what you know about mass and acceleration due to gravity?
When you jump vertically off the ground what is your acceleration when you reach your highest point

1) In this lab, you will use the Blackbody Spectrum Simulation to investigate how the spectrum of electromagnetic radiation emitted by objects is affected by the object’s temperature. In this simulation, you can input the temperature and observe the spectrum of the radiation emitted.
a) The temperature of stars in the universe varies with the type of star and the age of the star among other things. By looking at the shape of the spectrum of light emitted by a star, we can tell something about its average surface temperature.
i) If we observe a star’s spectrum and find that the peak power occurs at the border between red and infrared light, what is the approximate surface temperature of the star? (in degrees C)
ii) If we observe a stars spectrum and find that the peak power occurs at the border between blue and ultraviolet light, what is the surface temperature of the star? (in degrees C)
b) Light bulbs operate at 2500 degrees C.
i) What is the wavelength at which the most power is emitted for a light bulb operating at 2500 C?
ii) Explain why regular incandescent bulbs waste a lot of energy. Be sure to include your reasoning.
Go to http://phet.colorado.edu/simulations/sims.php?sim=Blackbody_Spectrum
and click on Run Now.
2) In this problem we will explore the greenhouse effect by using the Greenhouse Effect Simulation available from http://phet.colorado.edu/simulations/sims.php?sim=The_Greenhouse_Effect
a) Explore the simulation.
True or False
The only effect of increasing the number of clouds is to reduce the amount of sunlight absorbed by the surface of the earth.
True or False
Increasing the concentration of greenhouse gases, increases the amount of radiation that Earth emits to space.
True or False
When sunlight encounters a cloud, the cloud reflects about 10% of the sunlight back to space.
True or False
When there is a very large concentration of greenhouse gases, most of the IR radiation reaching space has interacted with greenhouse gas molecules on its way from the surface to space.
True or False
The total amount of radiation absorbed by the Earth’s surface is not affected by the concentration of greenhouse gases in the atmosphere.
True or False
At higher temperatures, the Earth’s surface emits more IR radiation.
True or False
During the ice age, the amount of sunlight absorbed by the Earth’s surface decreased.
True or False
All greenhouse gases are from anthropogenic sources (that is due to man’s activities).

(TCO 4) A ball is dropped from a 250 foot building. What is its velocity when it strikes the ground, ignoring any air resistance? (Points : 6)
(TCO 4) A bullet is fired vertically upward with an initial velocity of 250 m/sec. How high does it go? (Points : 6)
(TCO 4) A projectile is fired over level ground with an initial vertical velocity of 20 m/s and an initial horizontal velocity of 30 m/s. Using g = 10 m/s2, the distance from the launching to the landing points is (Points : 6)
(TCO 4) Two spacemen are floating together with zero speed in a gravity-free region of space. The mass of spaceman A is 120 kg, and that of spaceman B is 90 kg. Spaceman A pushes B away from him with B attaining a final speed of 0.5 m/s. The final recoil speed of A is (Points : 6)
(TCO 4) The speed of a body traveling in a straight line with a constant positive acceleration increases linearly with (Points : 6)
. (TCO 4) What is the velocity of an airplane that travels 500 km in 2 hours, 17 minutes? (Points : 6)
(TCO 4) A 4.0 kg object moving initially at 5.0 m/s along a straight line on a smooth (frictionless) surface is pulled a distance of 20.0 m by a constant force of 6.0 N acting along the same direction as the initial direction of the object’s motion. The final speed of the object is (Points : 6)
A ball is dropped from a 250 foot building. How long before the ball hits the ground? (Points : 6)
Suppose that while walking in a straight line at a uniform speed, you throw a ball straight up about 2 or 3 m without breaking stride. Where will it land? (Points : 6)
If a block of wood floats in water with two-thirds of its volume submerged, what is the density of the block? (Points : 6)
TCO 4) A hydraulic lift in a garage can lift a 1600 kg vehicle when a 400 N force is applied to the smaller piston of area 10 cm2. The area of the larger piston is (Points : 6)
(TCO 4) The small piston of a hydraulic press has an area of 10.0 cm2. If the applied force is 50.0 N, what is the area of the large piston so that the pressing force is 4800 N? (Points : 6)
Which of the following is the coldest temperature? (Points : 6)
The same amount of heat flows into four different materials. Which substance has the greatest specific heat? (Points : 6)
TCO 4) An ideal gas is heated. If the gas is in a container that prevents its volume from changing, what happens to the pressure? (Points : 6)
TCO 4) In a photoelectric effect experiment above the threshold frequency, the number of electrons ejected is proportional to (Points : 6)
TCO 4) Radio waves are readily diffracted around buildings, whereas light waves are negligibly diffracted around buildings. This is because light waves (Points : 6)
) Virtual images formed by a convex mirror are always (Points : 6
The charge on a glass rod which has been rubbed with silk is called positive (Points : 6
9. (TCO 4) A magnetic field cannot (Points : 6)
(TCO 4) A square loop of wire lies in the plane of the page as shown. A decreasing magnetic field is directed into the page. The induced current in the loop is
TCO 4) In an overhead straight wire, the current is north. The magnetic field due to this current, at our point of observation, is (Points : 6)
13. (TCO 4) Which of the following does not determine the resistance of a wire? (Points : 6)