1. A ball is projected up an incline and rolls around a track as shown above. At which two labelled points is the work done by the gravitational force on the ball not negative? Select two answers. 2. A single force is exerted on an object in the x
direction. Shown is a graph of that force and the displacement of the object in that direction. What amount of work is done for the 30 m shown?
a. 30J
b. 45J
c. 50J
d. 60J

3. An object of mass, m, hanging from the end of a
light string is initially at rest. It is lowered by the string a distance s and reaches a speed vf. How much work was done on the object by the string?

A single constant force is exerted on an object. The graph describes the object's energy. How much work was done to increase the speed of the object from 1.0 m/s to 3.0 m/s?
A. 1.5J
B. 2.0J
C. 4.0J
D. 4.5 J

5. A block of mass m initially at rest is pulled along
a plane inclined at 30° with the horizontal. At a height h it has kinetic energy Kf. The coefficient of friction with the incline is J. Which of the following correctly represents the net work done on the block?

An object of mass, mn, is attached to a spring hanging from the ceiling as shown. It is initially sup ported so the spring is unstretched. The object is released and falls. Which of the following correctly describes the kinetic energy of the object when it has fallen a distance h below the starting point?

Arise 8 run 1 this means go 8 up and 1 across, which is steepest

  sequence  is a continuous and distinctive band of  stars  that appears on plots of stellar  color  versus  brightness. these color-magnitude plots are known as  hertzsprung–russell diagramsafter their co-developers,  ejnar hertzsprungand  henry norris russell. stars on this band are known as  main-sequence stars  or  dwarf stars. these are the most numerous true stars in the universe, and include the earth's  sun.after condensation and ignition of a star, it generates  thermal energy  in its dense core region through  nuclear fusion  of  hydrogen  into  helium. during this stage of the star's lifetime, it is located on the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and age. the cores of main-sequence stars are in  hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of  gravitational collapse  from the overlying layers. the strong dependence of the rate of energy generation on temperature and pressure to sustain this balance. energy generated at the core makes its way to the surface and is radiated away at the  photosphere. the energy is carried by either  radiation  or  convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.the main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. stars below about 1.5 times the  mass of the sun  (1.5  m☉) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the  proton–proton chain. above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of  carbon,  nitrogen  and  oxygen  as intermediaries in the  cno cycle  that produces helium from hydrogen atoms. main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. below this mass, stars have cores that are entirely radiative with convective zones near the surface. with decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases. main-sequence stars below 0.4  m☉undergo convection throughout their mass. when core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.in general, the more massive a star is, the shorter its lifespan on the main sequence. after the hydrogen fuel at the core has been consumed, the star  evolves  away from the main sequence on the hr diagram, into a  supergiant,  red giant, or directly to a  white dwarf.

The big glowy thing is called the sun it is a star in our galaxy and is over 1 million degrees