warm up a swimmer is resting at the edge of the pool talking to his coach. the coach then begins...
TRANSCRIPT
Warm up• A swimmer is resting at the edge of the pool talking to his coach. The coach
then begins walking along the edge of the pool. The swimmer swims to the opposite edge to beat the coach. If the swimmer is walking with an average velocity of 2.5 m/s, how fast does the swimmer have to beat the coach to the opposite side? Dimensions of the pool 50 m by 25m.
Lab from Friday
• Use constant velocity to solve all problems• Average Walking velocity = 1m/s• Average Sprinting velocity = 5 m/s
• Classes that didn’t complete all sections , get data from other groups just reference them
Physics HonorsA/B–Day
10/06 – 10/07/152D motion
Agenda• 2 dimensional motion – Relative motion• Projectile motion• Examples
• Work on problems
Recall Vectors• Vectors have components
𝑉
𝑉 𝑥
𝑉 𝑦
• Vector components affect the resultant vector but not the other vector
• Let’s reduce the vector by
Recall Vectors• Vectors have components
𝑉
𝑉 𝑥
𝑉 𝑦
• Vector components affect the resultant vector but not the other vector
• Let’s reduce the vector by
• Observe how is unchanged
Example problem• A plane flies north at a velocity of 100 km/hr against a headwind of
25 km/hr. What is the resultant velocity?
Example problem• A plane flies north at a velocity of 100 km/hr with a tailwind of 25
km/hr. What is the resultant velocity?
Example problem• A plane flies north at a velocity of 100 km/hr with a sidewind of 25
km/hr east. What is the resultant velocity?
So how do we perceive relative motion• Relative motion
Which coordinate am I in?• If given resultant and then we are in Polar Form
• If given the components, then vector can be written in component form or unit vector notation.
Projectile Motion• What is a projectile?
What is a projectile and projectile motion?
• A projectile is any object that is only being accelerated by gravity.
• The objects we have been throwing up until now have been projectiles as well.
Ex. Throwing balls at an angle above the horizontal.
Ex. Throwing ball horizontally off a cliff.
Projectile Motion
Projectile Motion
Projectile Motion
Projectile MotionAt the maximum height
Projectile Motion
Projectile Motion
Projectile Motion
Projectile Motion• Ball has initial velocity
in the x and y directions
Projectile Motion• As ball goes into
motion, stays the same and gets smaller up until it reaches it maximum height
Projectile Motion• stays the same
• gets smaller up
Projectile MotionAt the maximum height
• is present with the same magnitude and direction
• = 0
Projectile Motion• As ball goes into down,
stays the same and gets larger down
Projectile Motion• stays the same
• gets larger down
Projectile Motion• Ball has returns to
ground with same magnitude as initial velocity in the x and y directions
• However has changed directions
How can we look at these motions
Horizontal Motion (x) Vertical Motion (y)
Velocity Constant Changing Acceleration No acceleration; a = 0 Constant a
So that means what about the equations we use in each direction
𝑣𝑎𝑣𝑔=∆ 𝑥∆ 𝑡
X – direction (Horizontal) y – direction (Veritcal)
Example Problem• A baseball is thrown at an angle of 25 at a velocity of 23.0 m/s. The ball was
caught at the same level it was thrown by a second player. • How long was it in the air? What was the highest point in the ball’s path? How
far away are the two players from each other?
Example Problem• Two kids are sliding a plate back and forth to each other. One misses
and it slides off the table. If the table is 1.05 m high and the plate flies off the table with a horizontal velocity of 0.74 m/s. How long does it take to fall to the ground? How far from the end of the table does it land?