course Phy 201 DҝŚЭgassignment #021
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00:29:56 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 intial vertical velocity is = 0 with the aceleration of gravity to be 9.8m/s^2 over a certian distance. Since we know these three quanties we can use the equation vf^2=v0^2+2a`ds to find final vertical velocity. We know the horizontal velocity remains constant. We take these two velocitys for are x,y components. We use the pythag. theorem to find the speed and tan^-1(y/x) to find the direction
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00:30:02
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RESPONSE -->
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00:30:39 ** 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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01:50:43 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 --> Pushing a mass up an incline: The x,y components will be the two forces amd the magnitude will be the total force and the angle is the direction of the mass Rolling a ball off a cliff:The x,ycomponents will be the final velocities of the horizontal and vertical fall. The magnitude will be the velcoity of the ball and the the angle the direction of the ball Two football players running into each other:gotta go
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01:51:03 ** 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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