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UNIT 2 Two Dimensional Motion And Vectors ConcepTest 3.4a A small cart is rolling at constant velocity on a flat track. It fires a ball straight up into the air as it moves. After it is fired, what happens to the ball? Firing Balls I 1) it depends on how fast the cart is moving 2) it falls behind the cart 3) it falls in front of the cart 4) it falls right back into the cart 5) it remains at rest ConcepTest 3.4a A small cart is rolling at constant velocity on a flat track. It fires a ball straight up into the air as it moves. After it is fired, what happens to the ball? In the frame of reference of the cart, the ball only has a vertical component of velocity. So it goes up and comes back down. To a ground observer, both the cart and the ball have the same horizontal velocity, so the ball still returns into the cart. Firing Balls I 1) it depends on how fast the cart is moving 2) it falls behind the cart 3) it falls in front of the cart 4) it falls right back into the cart 5) it remains at rest when viewed from train when viewed from ground Thursday/Friday September 22-23 Projectiles: Zero Launch Angle 4 TODAY’S AGENDA Thursday, September 22 Projectile Motion Mini-Lesson: Zero Launch Angle Problem Quiz 1 Vectors Hw: Complete Practice C Problems (all) UPCOMING… Fri: Mon: Tues: Wed: More Zero Launch Angle Projectile Motion @ any angle LAB 3: Projectile Motion Problem Quiz 2 Projectile Motion Projectile Motion Something is fired, thrown, shot, or hurled near the earth’s surface. 6 One Dimensional Projectile 7 Two Dimensional Projectile 8 Horizontal Component of Velocity 9 Horizontal Component of Velocity 10 Vertical Component of Velocity 11 Horizontal and Vertical Motion 12 Horizontal and Vertical Motion Perpendicular components of motion are independent of each other. 13 Launch Angle 14 Launch Angle 15 Zero Launch Angle Vo 16 Sample Problem 1) The Zambezi River flows over Victoria Falls in Africa. The falls are approximately 108m high. If the river is following horizontally at 3.60 m/s just before going over the falls, what is the final velocity of the water when it hits the bottom? Assume the water is in freefall as it drops. Find the time of flight Find the final vertical velocity = − = − = − = − − = −(. ) = . = (−. )(. ) = −. 17 1) continued… Find the time of flight Find the final vertical velocity Ө Final horizontal velocity = . + (−. ) = tan− −. . = . = −. = . = −. = −. ° = −. @ . ° (−) 18 Sample Problem 2) 19 Sample Problem 3) 20 Sample Problem 4) A lunch pail is accidently kicked off a steel beam on a building under construction. Suppose the initial horizontal speed is 1.50 m/s. a) How far does the lunch pail fall after it travels 3.50 m horizontally? 21 Sample Problem 4) A lunch pail is accidently kicked off a steel beam on a building under construction. Suppose the initial horizontal speed is 1.50 m/s. b) If the building is 2.50 x 102 m tall, and the lunch pail is knocked off the top floor, what will be the horizontal displacement of the lunch pail when it reaches the ground? 22 Sample Problem 4) A lunch pail is accidently kicked off a steel beam on a building under construction. Suppose the initial horizontal speed is 1.50 m/s. c) If the building is 2.50 x 102 m tall, and the lunch pail is knocked off the top floor, what is the final velocity the lunch pail when it reaches the ground? 23 Sample Problem 5) The LZ N07 is a newly designed airship in the manner of the old Zeppelin airships built in Germany between 1908 and 1940. This airship can travel with a horizontal speed of 1.30 x 102 km/h. If a parcel is dropped from this airship, so that it lands 135 m in front of the spot over which it was released, how far above the ground is the airship? 24 Sample Problem 6) A squirrel on a limb near the top of the tree loses its grip on a nut, so that the nut slips away horizontally at a speed of 10.0 cm/s. If the nut lands at a horizontal distance of 18.6 cm, how high above the ground is the squirrel? 25 END 26