Birth of Dynamics: Newton

The purpose of this page is to help you understand *Newtonian dynamics* and develop related skills. Be prepared to answer or do all the following:

**Section 1: Development of the theory:**

- Aristotle suggested that the earth is composed of four elementary substances, each with a
*natural place.*Indicate on a sketch where each substance belongs: - What were Aristotle's views on motion and their causes?
- To Aristotle, some motions were
natural,

and required nocause.

Which were*natural motions*? How were Newton's views different? - In what time period did Aristotle live?
- In what ways was the culture of Newton's time different from Aristotle's?
- Define scalar:
- Define vector:
- What is dynamics?
- What is kinematics?
- How does a jet engine make a plane go forward?
- Certain kinds of motions are considered natural. Describe those Aristotle considered natural, and those Newton considered natural:
- Why does a sky diver "feel" weightless?
- Why does an orbiting astronaut "feel" weightless?
- The SI unit for force is:
- If for every force there is an equal but opposite force, how can anything possibly move?

Circle the pairs of vectors that are equal:

In each of the six pairs of vectors above, find the difference between the top and bottom vectors (i.e., subtract).

Identify each of the following as

- a 20 knot wind blows out of the west
- SPEED LIMIT 55
- KEEP RIGHT
- travelling south at 2 p.m.

**Section 2: Mathematical section: Apply your understanding by making specific predictions.** List all equations you use, and show substitutions and algebra. Show your stepwise solution procedure. Answers need to be reported with the correct *uncertainty* (i.e., the correct number of *significant figures*), and appropriate *unit* labels:

- If a rock is dropped from a tall cliff on the moon where gravity is 0.165 that on earth, what will be the speed of the rock 9.0 seconds later?
- The sun has a mass of 2.0 x 10
^{30}kg; the earth has a mere mass of 6.0 x 10^{24}kg; still, the earths's gravitational pull on the sun is 1.4 x 10^{23}Newtons. What force does the sun's gravity pull on the earth? - Mountain View is 80 miles east and 100 miles south of Ocean Port. What is the air displacement Mountain View to Ocean Port? [Use a diagram to show direction.]
- If a south wind is blowing steadily at 40 miles/hr, and a small airplane has an air speed of 120 miles/hr, draw a scale diagram and determine which direction will be needed to fly from Sequim to Seatac, a town due southeast?
- What will a 50 kg person weight in an elevator acclerating upwards 1.0 m/s
^{2}? (I.e., what will be the force of the floor on this person?)

go to i.e. Physics menu,

or to site menu

created 16 September 2001

last revised 15 May 2010 by D Trapp

or to site menu

created 16 September 2001

last revised 15 May 2010 by D Trapp