Do you speculate that your present ideas about the world around you will change as you learn and experience more, or do you speculate that further knowledge and experience will solidify your present understanding? ) I see that as a strength, many people Just take for granted what was told to them as an unchanging fact, and it is the people who have questioned these facts that have truly reshaped our world in all aspects, not Just science and mathematics. 6. When you step from shade into the sunlight, the Sun’s heat is as evident as the coals in a fireplace in an otherwise cold room.
You feel the Sun’s heat, not because of its high temperature, but because the Sun is big. Which do you estimate is larger, the Sun’s radius or the distance between the moon and the Earth? Do you find your answer surprising? I estimated that the distance to the moon was slightly larger than the Sun’s radius, but in actuality the Sun’s radius is larger than the distance to the moon which was very surprising to me from the lower level science classes that I remember. 7. What is probably misunderstood by a person that says, “But that’s only a scientific theory’?
The process of formulating a scientific theory is a very tedious process consisting of analyzing many well-tested hypotheses and facts. Chapter 2 1 . What are the three major items of Aristotle that Galileo nullified? The first was his idea of motion, proving that weight doesn’t matter on time of falling objects, proving this by dropping different sized items off of the leaning tower of Pisa. 2. Who first introduced the word Inertia? Galileo first stated that everything tends to resist changes in motion and called it inertia. Newton’s first law was the law of inertia but it was Just expounding upon
Galileo original thought. 3. What is Newton’s First law of Motion? As previously stated, Newton’s first law was the law of inertia. This law states “Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force. ” 4. What is equilibrium rule? The equilibrium rule is basically describing something that has a net force of zero. Weight, the gravity is pulling the object down but it is not moving due to the strength of the string. 5. What is support Force and why is it important to understand it?
Support force is he potential amount of force or strength that an object has while it is stationary. The example that the textbook uses is that a book sitting on a table is stationary and not falling because of the table’s support force. It is important to understand because it is the potential of force and isn’t always acting upon something. 2. Copernicus postulated that Earth moves around the Sun, but he was troubled about the idea. What concepts of mechanics were he missing (later introduced by Galileo and Newton) that would have eased his doubts?
He was missing the concepts f inertia and net force in that Just because something seems to be stationary, it isn’t necessarily, it may have a net force of zero or it may not be accelerating or slowing down so that speed is actually acts upon all things equally like throwing a ball in a moving car. 4. What Aristotelian idea did Galileo demolish with his experiments with inclined planes? He demolished the idea that a vacuum would be impossible and all things are acted upon by some sort of medium, whether it be air, water or land to cause friction to an object. 5. Why do you lurch forward in a bus that suddenly slows? Why do you lurch backward when it picks up speed? What law applies here? This is the law of inertia at work, stating that all things tend to stay the same unless acted upon by another force, so the slowing of the bus makes your body want to continue at the same speed it was going, therefore moving forwards, the same with speeding up as you body lurches backwards to compensate in acceleration. 26. Can you say that no force acts on a body at rest?
Or is it correct to say no net force? Defend your answer. A body at rest has a zero net force since gravity is a instant force pushing a body down but it has the supportive force to stay whole. Also two kids pushing a grocery cart at the exact same NON rate, the cart will not move though it has forces being applied to it. 28. Harry the painter swings year after year from his boson’s chair. His weight is NON and the rope, unknown to him, has a breaking point of BOON. Why doesn’t the rope break when he is supported as shown on the left?
One day, Harry is painting near a flagpole, and, for a change, he ties the free end of the rope to the flagpole instead of his chair, as shown on the right. Why did Harry end up taking vacation vacation. On the left picture, he has his rope doubled over onto his chair with a pulley system, effectively only applying NON on each half of his rope but if it is only tied to his chair and another object, his full NON is applied to the rope that has a breaking limit of NON and down he goes. Chapter 3 1. What is the difference between Instantaneous Speed and Average speed?
Instantaneous speed is the speed at which something is moving at that exact moment in time whereas the average speed of something is calculated as the total stance covered over the time interval used. So over a 30 minute period a car could average mi/h but at an exact moment be traveling at Mimi/h but it wouldn’t be sustained. 2. What is the difference between Velocity and Acceleration. Give example. Velocity is the speed and direction that something is going while acceleration is a change in velocity.
If a car is traveling due East at Mimi/h, that is the velocity but if that car’s velocity changes to 51 mi/h, Mimi/h or turns 12 degrees to the west, it would be accelerating. 3. How did Galileo explain Acceleration by an inclined plane? Since he did not have accurate timing devices, he used planes at certain inclines to learn that balls rolling on them had unchanging acceleration, both upwards and downwards. He also showed that a vertical plane had the same acceleration as dropping the same object. 4. What is the meaning of Free Fall?
What becomes the acceleration in free fall? Free Fall is an object falling with no friction or wind resistance, basically falling under the force of gravity alone. The rate of this is usually rounded to mom/s though a more accurate rate of 9. Mm/s is used when more precise results are required. Exercises 5, 19, 20, 40, 41 5. Light travels in a straight line at a constant speed of 300,000 km/s. What is the acceleration of light? O, if light is always traveling in a straight line at an exact, constant speed, then it is never accelerating, changing direction or speed. 9. On which of these hills does the ball roll down with increasing speed and decreasing acceleration along the same path? The middle hill would have the ball moving downwards to start increasing speed as it goes until the angle begins to change, making the hill at that point much less steep. At that point the ball begins to 20. Suppose that the three balls shown in Exercise 19 start simultaneously from the tops of the hills. Which one reaches the bottom first? Explain.
The ball on the second hill would land first because it has such a large acceleration at the top of the hill that the other balls would not be able to catch up despite there being a period of deceleration. 40. Two balls are released simultaneously from rest at the left end of equal-length tracks A and B as shown. Which ball reaches the end of its track first? If both balls are dropped simultaneously, the ball on track B reaches the end first since the speed s increased for such a time before it is decreased again to match the speed on track A. 1. Refer to the pair of tracks in Exercise 40. (A) On which track is the average speed greater? (B) Why is the speed of the ball at the end of the tracks the same? (A) The average speed is greater on track B since it accelerates during the dip and then when it has a deceleration but the speed only drops to that of the other track. (B) The acceleration is the exact same rate of change as the deceleration later in the track so the speed at the very end is equal to track A with no changes.