Transcript File
Bell work (10/6): 1. Copy down the new lesson objective onto your personal Unit II Blank Unit Cover Page 2. In nature, would a bullet dropped & a bullet fired perfectly horizontal hit the ground at the exact same time? Why or why not? Mythbusters’ Slides *** Mythbusters Slides Here Vector Independence Motion in the x-direction (horizontal) is not affected by motion in the y-direction (vertical) & vice-versa HOW MIGHT THIS BE A USEFUL TOOL FOR US TO USE A PHYSICISTS? Projectile Motion VERTICAL DIR. (Y) 1 2 y f = yo + vy,ot + gt 2 HORIZONTAL DIR. (X) dx vx = t Bell work (10/7): A friend claims that bullets fired by some high-powered rifles travel for many meters in a straight-line path before they start to fall. Another friend disputes this claim and states that all bullets from any rifle drop beneath a straight-line path a vertical 2 distance given by (d=1 2 gt ) and that the curved path is apparent for low velocities and less apparent for high velocities. Now it's your turn: Will all horizontally fired bullets drop the same vertical distance in equal periods of time? Explain no fewer than 4 complete sentences. Projectile Motion Question #1 A ball rolls with a speed of 2.0 m/s across a level table that is 1.0 m above the floor. Upon reaching the edge of the table, it follows a parabolic path to the floor. How far along the floor is the landing spot from the table? Projectile Motion Question #2 A rescue pilot drops a survival kit while her plane is flying at an altitude of 2000.0 m with a forward velocity of 100.0 m/s. If air friction is disregarded, how far in advance of the starving explorer’s drop zone should she release the package? Projectile Motion Questions # 3 An arrow is shot horizontally at a speed of 40 m/s from a bow held 1.5 meters above the ground. It misses the target and hits the ground. a) How much time does it take for the arrow to hit the ground? b) What is the range of the arrow? c) What is the arrows vertical velocity after 0.25 seconds? Projectile Motion Question #4 A cliff diver must clear rocks that extend 15 meters out from the cliff ’s edge when diving from a cliff that is 40 meters above the water below. a) How much time passes before the diver hits the water after jumping? b) What minimum horizontal speed must the diver have to just clear the rocks below? c) What is the diver’s horizontal velocity after 2 s? Vertical velocity after 2 s? Exit Ticket – Proj. Motion Q. #5 A rifle is fired horizontally and travels 200.0 m. The rifle barrel is 1.90 m from the ground. How long was the bullet in the air before striking the ground Bell work (10/8): A hungry coyote pushed horizontally off a high cliff at a speed of 25 m/s. He hits the canyon floor below 5.8 seconds later. a) How high is the cliff ? b) How far out from the cliff edge does he land in the canyon below? Review HW With partner, review last night’s HW: For those that are incorrect, begin to work out correct solutions with your partner Select one problem you would like Mr. C. to work out with the entire class. Projectile Motion Question #6 A rifle is aimed horizontally at shoulder height (1.5 meters above the ground) at a target bulls eye 700 meters away. The bullet leaves the barrel with a muzzle velocity of 1000 m/s. a) Does it reach the target? b) If not, where on the ground does it hit? Projectile Motion Question #7 A rock is thrown horizontally from the top of a cliff 98 m high, with a horizontal speed of 27 m/s. a) For what interval of time is the rock in the air? b) How far from the base of the cliff does the rock land? c) What is the rock’s horizontal velocity after 2 s? Vertical velocity after 2 s? Projectile Motion Question #7 A rock is thrown horizontally from the top of a cliff 98 m high, with a horizontal speed of 27 m/s. a) For what interval of time is the rock in the air? b) How far from the base of the cliff does the rock land? c) What is the rock’s horizontal velocity after 2 s? Vertical velocity after 2 s? What is the rock’s resultant velocity at t = 2 seconds? Projectile Motion Question #4 Revisited A cliff diver must clear rocks that extend 15 meters out from the cliff ’s edge when diving from a cliff that is 40 meters above the water below. a) How much time passes before the diver hits the water after jumping? b) What minimum horizontal speed must the diver have to just clear the rocks below? c) What is the diver’s horizontal velocity after 2 s? Vertical velocity after 2 s?