Query 21

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course Phy 121

021. `query 21*********************************************

Question: `q 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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Your solution: Horizontal velocity is unchanging so the horizontal component is equal to the initial horizontal velocity. In the equations usually the vertical velocity starts at rest with the acceleration 9.8m/s^2 downward. With this you can find the final velocity by using the fourth equation of motion. To find speed and direction of motion you can use the Pythagorean Theorem and arctan (vy/vx).

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Given Solution:

`a** 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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Self-critique (if necessary):

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Self-critique Rating: Ok

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Question: `q 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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Your solution: A force acting on an object causing it to move in an angular direction. A ball falling to the ground off a ramp with a certain velocity and angle. A two ball collision; velocity and momentum are both vector quantities and both important for analyzing the collision. The velocity and direction of travel uses magnitude and direction of the resultant The vector components are the horizontal and vertical components that would produce the same effect as the resultant. A car rolling down the hill with velocity and momentum are both vector quantities and important.

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Given Solution: 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 direction of the resultant 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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Self-critique (if necessary):

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Self-critique Rating: Ok

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&#This looks very good. Let me know if you have any questions. &#