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Kinematics in two dimensions. Position Displacement Average Velocity (Instantaneous) Velocity Average Acceleration (Instantaneous) Acceleration. Instantaneous velocity and acceleration. 1 - D. 3 - D. 0. 0. 0. Constant acceleration. Projectile Motion. Mortars, artillery, and guns.
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Kinematics in two dimensions • Position • Displacement • Average Velocity • (Instantaneous) Velocity • Average Acceleration • (Instantaneous) Acceleration
1 - D 3 - D 0 0 0 Constant acceleration
Mortars, artillery, and guns Motion is parabolic!
2004 Report on the status of the Army Artillery School • ...And student officers with reading and math skills below seventh-grade level have been allowed to recycle multiple times before being force-fed to their units - even though an artillery officer who can't do math is like a fireman who's allergic to smoke. • Columnist and former soldier David H. Hackworth is the author of The Price of Honor, and contributes weekly commentary to DefenseWatch
Example Problem • A batter hits a pitched ball whose center is 4.0 feet above the ground so that is angle of projection is 45 degrees and its range is 350 feet. The ball will be a home run if it clears a 24 ft high fence that is 320 feet from home plate. Will the ball clear the fence? If so, by how much?
Uniform Circular Motion • Uniform = magnitude of velocity (speed) is not changing
Uniform Circular Motion Terms • Frequency (f) – The number of revolutions (cycles) completed in a second. • Period (T) – The time to complete one revolution (cycle).
Uniform Circular Motion Example • A particle moves in a circular path 0.40 m in radius with constant speed. The particle makes 5.0 revolutions in each second of its motion. • Find the particle’s speed • Find the particle’s acceleration 13 m/s 390 m/s2
Relative Motion The velocity of an object relative to stationary reference frame is equal to the velocity of an object relative to a moving reference frame plus the velocity of the moving reference frame.
017 9.5 kts Relative Motion There is a 3 knot westerly current. Your ship is doing 10 knots by log. What course must you steer to make course north good? What will be your speed over ground?
135/10kts Mo Boards 0 1000 yds 3 min 090/15kts