Answer:
Average speed = distance/time
From 1 to 9 seconds:
Distance covered = 1 - 0.2 = 0.8 km
Time = 9 - 1 = 8 sec
Average speed = 0.8 km / 8 sec
Average speed = 0.1 km/s .
The average speed for the whole test is 1.6 km / 20 sec = 0.08 km/sec. A graph of speed vs time would average out as a horizontal line at 0.08 km/sec from 1 sec to 21 sec. The area under it would be (0.08 km/s) x (20 sec) = 1.6 km.
Surprise surprise ! The area under a speed/time graph is the distance covered during that time !
In closing, I want to express my gratitude for the gracious bounty of 3 points with which I have been showered. Moreover, the green breadcrust and tepid cloudy water have also been refreshing.
Explanation:
Answer: Open system
According to thermodynamics, if a system exchanges matter and energy with its environment it is an open system. For example, human beings and animals can be considered as open systems, since we take chemical energy in the form of food and perform work on our surrounding environment when moving and doing activities.
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Answer:
c. Your body is at rest but its inertia puts it in motion
Explanation:
The horse's position on the ground at time <em>t</em> is
<em>x</em> = (20 m/s) <em>t</em>
The baboon's height from the ground at time <em>t</em> is
<em>y</em> = 3 m - 1/2 <em>g</em> <em>t</em>²
where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity.
The baboon falls and lands on the horse, so that the two animals meet when the baboon's height is 2 m from the ground, which happens after
2 m = 3 m - 1/2 <em>g</em> <em>t</em>²
1/2 <em>g</em> <em>t</em>² = 1 m
<em>t</em>² = (2 m) / (9.80 m/s²)
<em>t</em> ≈ 0.452 s
In this time, the horse reaches the tree, so its distance from it is
(20 m/s) * (0.452 s) ≈ 9.04 m
Answer:
C, 4.5 billion years ago, i think
Explanation:
