Principle of Environmental Physics

ESC 3006: Principle of Environmental Physics

Group 2

Homework Assignment #2

Mohamad Faiz Zainuddin

Due: 1st October 2015 before lab #2

Question #1-2 are taken from concept ch_02 slides

1. You drive for 4 miles at 30 mi/hr and then another 4 miles at 50 mi/hr. Find the average speed for the whole 8 mile trip. Then find the distance you need to travel at 50 mi/hr to achieve the average speed of 40 mi/hr. Verify your answer.

2. A ball is thrown straight upward with an initial speed.  When it reaches the top of its flight (at a height h), a second ball (identical in materials and mass) is thrown straight upward with the same initial speed.  Derive an equation to prove that the height at which both balls cross path, yc, is indeed greater than h/2?

3. Find the distance of path ABCD in terms of unit. The coordinate for each point is as follows: A (0,7,0), B(0,-7,0), C(0,07), D(-7,0,0). Half circle ABO is located on xy plane, quarter-circle BCO on yz plane and quarter-circle DCO on xz plane. If it takes 10 s to get from point A to point B, 6 s to get from point B to point C and 6 s to get from point C to point D, what is the average speed from point A to point D in unit/second.

[pic 1]

4. 6. A rural mail carrier leaves her post office and drives 10 km in the east direction. She then drives for 5 km in the north direction. What is her displacement from the post office? Sketch all related vectors on a Cartesian coordinate.