physics revision
The Big Bang and the Evolution of the Universe Until Today – pg. 163-166 1. What do scientists believe was the beginning of the universe? Scientists believe the beginning of the universe was the big bang. 2. Give 2 pieces of evidence to support this theory. Red shift and that the temp. Of the universe is still cooling down. 3. Starting with the earth, list, in order of size, the main components of the universe. You should be able to list at least 5 different components. Earth, solar system, galaxy, galaxy clusters, universe. 4. How do stars form? State the major steps in their formation, starting with hydrogen gas. Hydrogen gas – particles come together w/ gravity because of high pressure and temp. Fuse together and form helium. 5. What are the two main forces which are acting on a star when it is in equilibrium. Gravity and expansion. 6. What has to happen to a star in order that it turns into a red giant? It blows up with hydrogen gas and gravitational force becomes too strong – collapses in. Then gets hot again. 7. Name three possible final outcomes for a star when it runs out of hydrogen fuel. Black hole, nutron star, which dwarf, black dwarf. Newtonian Mechanics – pg. 130-135, 144-146 1. What are the definition of units of speed? Speed = distance/time m/s. 2. What are the definition and units of acceleration? Acceleration = change in velocity/time take to change. 3. What is the difference between speed and velocity? Velocity is a vector quantity and has a size (speed) and a direction. 4. Sketch distance-time graphs for an object which si travelling at: a) constant speed b) constant acceleration On seperate sheet. 5. Sketch speed-time graphs for an object which is travelling at: a) constant speed b) constant acceleration On seperate sheet. 6. How can a speed time graph be used to determine the distance traveled by a car traveling at constant acceleration. Distance travelled = area under the graph 7. What is the acceleration of an object falling freely close to the surface of the earth? 9.8m/s 8. Under what circumstances does an object reach terminal velocity. When there are equal forces acting over and under an object. 9. What are the units of mass? Kg 10. What are the units of weight? Newtons 11. How can you measure the mass of an object? Lever balance. 12. How can you measure the weight of an object?