Arrange the following main sequence stars in order of decreasing surface temperature: yellow stars, blue stars, white stars, red stars.

A centimeter is

Match the letters below with the correct choice on the right. Selections on the right may be used once, more than once, or not at all.  The proportionality between the galactic speed and distance was discovered in 1929 by the astronomer Edwin Hubble and is known as Hubble’s law. This law states that the ___A___ the distance of galaxies from earth, the faster the galaxies are traveling. The universe, in other words, is ___B___ with the result that its component galaxies are moving further apart. The ___C___ shift in the light from a galaxy is determined by how much the universe has expanded since the galaxy emitted the light.

The surface temperature of the sun is about:

A 50 kg woman runs up a staircase 5m high in 20s. The work done is ___A___. The power developed in this process is ___B___. Use acceleration due to gravity g = 10 m/s2.

What happens with a block of wood with the density dwood = 700 kg/m3 after it is dropped in a pool of water and reaches equilibrium (stops)? dwater = 1000 kg/m3

Find the heat needed when temperature of a 0.25 kg piece of gold is changing from 10 ºC to 90 ºC (specific heat for gold is s gold= 129 J/kg·ºC).

Match the letters below with the correct choice on the right. Selections on the right may be used once, more than once, or not at all. Write the two Principles of Thermodynamics. Give an example with efficiency connection. 1. ___A___ cannot be created or destroyed, but it can be converted from one form to another. In terms of efficiency this law can be expressed as ___B___. 2. It is impossible to take ___C___ from a source and change all of it to mechanical energy or work; some heat must be wasted. In terms of efficiency this law can be expressed as ___D___.

An annular eclipse of the sun occurs when the

Match the letters below with the correct choice on the right. Selections on the right may be used once, more than once, or not at all. A soccer ball is dropped in a vacuum chamber. Describe the motion and show how the energy is transforming from a form to the other. Total energy is the sum of kinetic and ___A___ energy. Kinetic energy is the energy of a moving object and it depends on the object’s mass and its ___B___. Potential energy is the energy of position and the gravitational potential energy depends on the ___C___ above its original position. Because the motion of the ball takes place in a vacuum chamber the total energy is ___D___ (no friction). The total energy transforms from one form to the other. When the ball is released from the top of the chamber at rest all its energy is ___E___. As the ball falls, height decreases and the speed increases. At the end of the chamber (just before hitting the bottom) all its energy is ___F___.