ANALYZE (A) Find the final speed for a launch angle of -20°. For positive launch angles, as the ball first moves upward,

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Analyze A Find The Final Speed For A Launch Angle Of 20 For Positive Launch Angles As The Ball First Moves Upward 1 (709.13 KiB) Viewed 37 times

ANALYZE (A) Find the final speed for a launch angle of -20°. For positive launch angles, as the ball first moves upward, its potential energy increases while the magnitude of its vertical velocity decreases, decreasing its kinetic energy. Afterward, during the downward part of its motion, its potential energy decreases as the speed of its downward motion increases, and this increase in speed corresponds to an increase in kinetic energy. Throughout the motion of the ball, its total mechanical energy Emech - K+U - mvo? + mgh remains constant, and therefore equal to its initial value: Emech - mvo? + mgh. he ball reaches the ground at height o, the total mechanical energy is Emech – mu? Equating the two expressions for Emech gives vp=Vvo? + 2gh - V (12.50 m/s)2 + 2(9.8 m/s?)(25.50 m) - x m/s. (B) Find the final speed for a horizontal launch. Because the total mechanical energy does not change, the change in kinetic energy depends only on the change in potential energy, which depends only on the difference of initial and final height, rather than on the detailed path in between. Launching the ball horizontally at the given speed instead of vertically leaves the difference between final and initial heights unchanged, so that the speed upon reaching the ground is X m/s. FINALIZE Although changing the launch angle for a given launch speed does not change the speed of the ball when it reaches the ground, can it affect the magnitude of the vertical component of velocity when the ball strikes the ground? If so, what launch results in the ball striking the ground with the strongest vertical component of velocity? Need Help? Talk to a Tutor Submit Answer