Today we began our venture into Newton's Laws. To be honest, everything we've been working with so far has led up to this. Velocity, acceleration, vectors, linear motion has all been leading up to us gaining a strong understanding of Newton's three laws of motion. Today we began with Newton's first law, an object in motion stays in motion and an object at rest stays at rest unless a force acts against them.
Homework for this week is to:
Read pgs. 43-55
Review Questions pg. 56 #'s 1-10
Also, I want to get a bit deeper into these vector questions so please try to answer the following questions. Let me know if you need some help on these. I gave some clues in the first question.
1. a. Suppose that a boat was moving directly across a current with a velocity of 3 m/s, North and the motor boat was moving with a velocity of 4 m/s, East. What would the resultant velocity of the motor boat be. (i.e., the velocity relative to an observer on the shore)?
b. If the width of the river is 10 meters wide, then how much time does it take the boat to travel shore to shore? (For this, just forget about the current. How long would it take the boat to get from shore to shore (go 10 meters) moving at 4m/s?)
c. What distance downstream does the boat reach the opposite shore? (Use the time in part b for this. How far downstream would the boat travel in that amount of time?)
2. A motor boat traveling 4 m/s, East encounters a current traveling 7.0 m/s, North.
a. What is the resultant velocity of the motor boat?
b. If the width of the river is 80 meters wide, then how much time does it take the boat to travel shore to shore?
c. What distance downstream does the boat reach the opposite shore?
3. A motor boat traveling 6 m/s, East encounters a current traveling 3.8 m/s, South.
a. What is the resultant velocity of the motor boat?
b. If the width of the river is 120 meters wide, then how much time does it take the boat to travel shore to shore?
c. What distance downstream does the boat reach the opposite shore?
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