Query 21

course PHY 201

July 14 around 8:00 pm

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:

The final speed of a projectile can be obtained from the vertical distance and the known velocity in the horizontal direction. We need to find the vertical and horizontal final velocities, which will give us the final speed. This can be found by using the fourth equation of the uniform accelerated motion. Then, once you have the vertical velocity you can find the direction of motion by using: angle = tan-1(y/x).

Confidence rating #$&*: 3

.............................................

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):

OK

Self-critique rating #$&* 3

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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 kid running in a direction with a known displacement.

A rock being thrown down a well with a know velocity and vertical displacement.

A ball being thrown at a certain acceleration off of a building with the known displacement.

The magnitude and direction are the know quantities in the situations and needing to find the vertical and horizontal quantities.

Confidence rating #$&*: 2

.............................................

Given Solution:

`a

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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Self-critique (if necessary): OK

Self-critique rating #$&* 3

"

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

#$&*

Query 21

course PHY 201

July 14 around 8:00 pm

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.

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

The final speed of a projectile can be obtained from the vertical distance and the known velocity in the horizontal direction. We need to find the vertical and horizontal final velocities, which will give us the final speed. This can be found by using the fourth equation of the uniform accelerated motion. Then, once you have the vertical velocity you can find the direction of motion by using: angle = tan-1(y/x).

Confidence rating #$&*: 3

.............................................

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. **

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Self-critique (if necessary):

OK

Self-critique rating #$&* 3

*********************************************

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.

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

A kid running in a direction with a known displacement.

A rock being thrown down a well with a know velocity and vertical displacement.

A ball being thrown at a certain acceleration off of a building with the known displacement.

The magnitude and direction are the know quantities in the situations and needing to find the vertical and horizontal quantities.

Confidence rating #$&*: 2

.............................................

Given Solution:

`a

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.

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Self-critique (if necessary): OK

Self-critique rating #$&* 3

"

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

#$&*