course Phy 121 assignment #021ýºä´îõ|¶©îšõiÃæ¼·³—ÑZãLë
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11:59:01 Explain how to obtain the final speed and direction of motion of a projectile which starts with known velocity in the horizontal direction and falls a known vertical distance, using the analysis of vertical and horizontal motion and vectors.
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RESPONSE --> The horizontal velocity is constant and this means the the initial and final horizontal velocity. Since the projectile is falling then acceleration occurs from a vertical velocity at 0 m/s and continues downward at 9.8 m/s^2. Using the equation vf^2 = v0^2 + 2a`ds you can find the final vertical velocity. To find speed and direction you can use Pythagoreans Thm. and the arctan of vy and vx.
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11:59:23 ** The horizontal velocity is unchanging so the horizontal component is always equal to the known initial horizontal velocity. The vertical velocity starts at 0, with acceleration thru a known distance at 9.8 m/s^2 downward. The final vertical velocity is easily found using the fourth equation of motion. We therefore know the x (horizontal) and y (vertical) components of the velocity. Using the Pythagorean Theorem and arctan (vy / vx) we find the speed and direction of the motion. **
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RESPONSE --> ok
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12:19:52 Give at least three examples of vector quantities for which we might wish to find the components from magnitude and direction. Explain the meaning of the magnitude and the direction of each, and explain the meaning of the vector components.
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RESPONSE --> Force due to gravity causes a ball to roll down an incline from rest. When two objects roll to each other and collide velocity and momentum can each be determined. Velocity is the distance the object travels divided by the time it takes to travel. Momentum is the mass times a velocity of an object. When a softball pitcher begins pitching a ball you can find the amount of energy needed or being used to complete the pitch and the velocity upon release until the ball hits the catchers mitt which tells you how fast the pitcher is throwing the ball.
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12:19:56 ** GOOD STUDENT RESPONSE: Examples might include: A force acting on an object causing it to move in an angular direction. A ball falling to the ground with a certain velocity and angle. A two car collision; velocity and momentum are both vector quantities and both important for analyzing the collision.. The magnitude and directiohn of the relsultant is the velocity and direction of travel. The vector components are the horizontal and vertical components that would produce the same effect as the resultant.
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RESPONSE --> ok
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