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Vectors and 2d-Kinematics Continued. Relevant Equations How to use them Homework Hints. Hyperphysics -Trajectories. http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html. Projectile Motion Quantities. Initial velocity speed,angle. Maximum Height of trajectory, h= y max. “Hang Time”
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Vectors and 2d-KinematicsContinued Relevant Equations How to use them Homework Hints
Hyperphysics-Trajectories http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html
Projectile Motion Quantities Initial velocity speed,angle Maximum Height of trajectory, h=ymax “Hang Time” Time of Flight, tf Range of trajectory, D Height of trajectory at arbitrary x,t
Maximum Height of Trajectory Height of trajectory,h=ymax
Angle for Maximum Range MAXIMUM range OCCURS AT 450
Height of Trajectory at time t or position x Height of trajectory, y(t) Height of trajectory, y(x)
Projectile Trajectory Equations Maximum height Time of Flight (“Hang Time”) Range of trajectory Height of trajectory as f(t) , y(t) Height of trajectory as f(x), y(x)
Field Goal Example A field goal kicker can kick the ball 30 m/s at an angle of 30 degrees w.r.t. the ground. If the crossbar of the goal post is 3m off the ground, from how far away can he kick a field goal? y x 3 m D y-direction voy = vo sin(30o) = 15 m/s y = yo + voyt + ½ at2 3 m = 0 m + (15 m/s) t – ½ (9.8 m/s2) t2 t = 2.8 s or t = 0.22 s. x-direction vox = vo cos(30o) = 26 m/s D = xo + vox t + ½ at2 = 0 m + (26 m/s)(2.8 s) + 0 m/s2 (2.8 s )2 = 72.8 m Illini Kicks 70 yard Field Goal
Homework Hints – Stadium Wall Calculate time to reach wall using vx: Calculate y position at time to reach wall:
Homework Hints-Catch 2 Vxis constant ! v Kinetic energy should be same as when ball was thrown. Y-component of velocity would be downward.
Homework Hints-Catch 2 Same conditions as before
Trigonometric Identity for range equation http://mathworld.wolfram.com/Sine.html http://mathworld.wolfram.com/Cosine.html
Trigonometric Identities relating sum and products List of trigonometric identities
Hyperphysics-Trajectories http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html