2.Chapter 4: [linear motion]straight line motionthat was ONLY vertical or ONLY horizontal motion
3. Chapter 5: looks at motion that followsa diagonal path or a curved path
6. vertical motion is not affected by the horizontal motion. And the horizontal motion is not affected by the vertical motion.
7. Observe: a large ball bearing is dropped at the same time as a second ball bearing is fired horizontally.
Remember adding 2 perpendicular vectorshorizontal and vertical vectors.
8. Remember: When we add perpendicular vectors we use Pythagorean theorem to find the resultant.
12. Suppose the motor moves the boat at 15 m/sec.how fast will the boat travel downstream [with the current]?
Total velocity traveling downstream: Vtotal= Vboat + Vcurrent= 15 + 8 = 23 m/sec
14.Using motor against the current: total velocity traveling upstream [AGAINST the current] Vtotal = Vboat –Vcurrent
15. Going upstream: Velocity of current and boat are opposite directionsVtotal = Vboat –Vcurrent
16. If there was no current, how many seconds for the boat to travel 120 meters to reach the opposite side?
time = distance velocitytime = 120 m 15 m/sectime = 8 seconds
But there if is a current, what happens when you try to go straight across the river from A to B?
18. If there is a current, The boat still crosses in 8 seconds, but it lands downstream at point C
19. Add the perpendicular velocity vectors add to find the resultant velocity
20. In this example, Every second the boat travels 15 meter in the x direction IT ALSO TRAVELS 8 meter in the y direction
Velocity = distance timeso distance = velocity X timedistance = 8 m/sec X 8 sec = 64 m
21) If you want to go from A to B instead, you must point the boat diagonally upstream to compensate for the current.
25. crosswind: blows plane off course [wind perpendicular to direction of plane]
How many seconds to cross? From A to BT = D/VT = 120/12.7 T = 9.4 sec