(a) The ball's height <em>y</em> at time <em>t</em> is given by
<em>y</em> = (20 m/s) sin(40º) <em>t</em> - 1/2 <em>g t</em> ²
where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity. Solve <em>y</em> = 0 for <em>t</em> :
0 = (20 m/s) sin(40º) <em>t</em> - 1/2 <em>g t</em> ²
0 = <em>t</em> ((20 m/s) sin(40º) - 1/2 <em>g t</em> )
<em>t</em> = 0 or (20 m/s) sin(40º) - 1/2 <em>g t</em> = 0
The first time refers to where the ball is initially launched, so we omit that solution.
(20 m/s) sin(40º) = 1/2 <em>g t</em>
<em>t</em> = (40 m/s) sin(40º) / <em>g</em>
<em>t</em> ≈ 2.6 s
(b) At its maximum height, the ball has zero vertical velocity. In the vertical direction, the ball is in free fall and only subject to the downward acceleration <em>g</em>. So
0² - ((20 m/s) sin(40º))² = 2 (-<em>g</em>) <em>y</em>
where <em>y</em> in this equation refers to the maximum height of the ball. Solve for <em>y</em> :
<em>y</em> = ((20 m/s) sin(40º))² / (2<em>g</em>)
<em>y</em> ≈ 8.4 m
Cups
teaspoon
tablespoon
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inches
<span>a.The hiker had an easy, level trail from 11:00-12:00 and was able to travel the fastest during that time period.---> may be because this was indeed fastest stage
b.The hiker got tired and walked the slowest from 1:00-2:00.---> no, because this was not the slowest stage
c.The hiker stopped for lunch from 11:00-12:00 and that slowed him down.---> no because this was the fastest stage
d.The hiker ended up in the same place that he started.---> no, because the hiker walked more toward east than toward west and more toward south than toward north.
Answer: option a) </span>
The line at the bottom of the picture ... probably the first line on a list of choices .. is the correct equation.
Answer:
0.000234 seconds
Explanation:
Since the row is 0.15m, its radius of rotation must be 0.15 / 2 = 0.075 m
We can start by calculating the angular speed of the rod:
Since one revolution equals to 2π rad. The speed in revolution per second must be
26800 / 2π = 4265 revolution/s
The number of seconds per revolution, or period, is the inverse:
1/4265 = 0.000234 seconds
