Today’s soundtrack is Sarah Brightman: La Luna, an album that I think is a perfect combination of Brightman’s gorgeous voice with symphonic pop. I especially love her tasteful cover of Simon & Garfunkel’s “Scarborough Fair.”
Everything You Need to Ace Science in One Big Fat Noteook
Chapter 9: Motion
As of this chapter, we’re in the third unit of this book, “Motion, Forces, and Work,” which should be a fun one!
The chapter is called “Motion.” But what exactly is motion? Motion is a change of position. It’s movement. It’s when an object’s speed is different from the speed of its reference point. Thus, all “motion is relative” (p. 92).
Speed is units of distance per units of time – for example, kilometers per hour, or meters per second. Speed is calculated thus: speed = distance / time. Speed can be calculated in two ways: average speed and instantaneous speed. The former is the total distance divided by the total time; the latter is “the speed at a certain given moment” (p. 93).
Remember running “suicide sprints” in your high school gym? You would start at the end line, run to the free throw line, run back to the end line, run to the foul line, run back to the end line, run to the centre line, run back to the end line, run to the far foul line, run back to the end line, and so on. If you played sports, your average speed may have been pretty good, but what was your velocity?
This is because velocity can be thought of as “speed in a certain direction” (p. 94). Velocity can be changed by either changing direction or speed. Changes to velocity are called acceleration, which is calculated with the formula acceleration = (final velocity – initial velocity) / time. An increase in speed is referred to as positive acceleration; a decrease in speed is referred to as negative acceleration (or deceleration).
- The formula for speed is s=d/t.
- If a dolphin swims 56 meters in 8 seconds and a walrus swims 30 meters in 6 seconds, the dolphin is faster.
- Motion is relative because we always use a point of reference, and in the grand scheme of the universe, nothing is actually stationary. For example, the earth is rotating very quickly, but because we are rotating at the same speed, we don’t perceive the earth’s motion.
- The information required to know the velocity of an object is its direction and its speed.
- If I walk around a square block at a constant pace, I would record four values of velocity, but only one value of speed.
- If a truck that is driving 30 km/h makes a u-turn and starts driving 30 km/h in the opposite direction, the driver’s instantaneous speed hasn’t changed, but the velocity has changed, since the direction of travel has changed.
- If a bee is flying in a circle at a constant speed, the bee is accelerating, since its velocity is constantly changing.
- The three ways that something can accelerate are positively, negatively, and directionally (my spell check says this isn’t a word…but it should be).
Systematic Theology (Wayne Grudem)
Chapter 2: The Word of God
There are two forms of the Word of God: First, Jesus Christ; second, speech by God.
References to Jesus as the Word of God exist in scripture (though they are rare). The usage of this phrase to refer to Jesus shows us that Jesus “has the role of communicating the character of God to us and of expressing the will of God for us” (p. 47).
There are four categories of the Word of God as speech by God. First, God’s decrees: his commandments “that cause events to happen or […] cause things to come into being” (p. 47), and even allows “the continuing existence of all things” (p. 48). Second, God’s words communicating to his people: they are understandable to the people to whom he speaks; God speaks to His people in human language. Third, God’s word can come through human lips in the form of the prophesies recorded in the Bible. Lastly, the fourth form of God’s word as speech is the written form: Scripture, which is “absolutely authoritative and absolutely true” (p. 50). In our study of systematic theology will be on this last form of God’s Word.
That’s it for today!