Answer: they used seasonal wind, temperature changes, they also used the flooding of rivers. all these are used to tell time
Explanation: the seasons change the climate of the area
Answer:
= 2630.6 N.m
Explanation:
(FR)x = ΣFx = -F4 = -407 N
(FR)y = ΣFy =-F1-F2 -F3 = -510 - 306 - 501 = -1317 N
(MR)B =ΣM + Σ(±Fd)
= MA + F1(d1 +d2) + F2d2 - F4d3
= 1504 + 510(0.880+1.11) +306(1.11) - 407(0.560)
= 2630.64 N.m (counterclockwise)
Answers:
a) 
b) 
c) 
d) 
Explanation:
For this situation we will use the following equations:
(1)
(2)
Where:
is the <u>height of the model rocket at a given time</u>
is the i<u>nitial height </u>of the model rocket
is the<u> initial velocity</u> of the model rocket since it started from rest
is the <u>velocity of the rocket at a given height and time</u>
is the <u>time</u> it takes to the model rocket to reach a certain height
is the <u>constant acceleration</u> due gravity and the rocket's thrust
<h2>a) Time it takes for the rocket to reach the height=4.2 m</h2>
The average velocity of a body moving at a constant acceleration is:
(3)
For this rocket is:
(4)
Time is determined by:
(5)
(6)
Hence:
(7)
<h2>b) Magnitude of the rocket's acceleration</h2>
Using equation (1), with initial height and velocity equal to zero:
(8)
We will use 
:
(9)
Finding :
(10)
<h2>c) Height of the rocket 0.20 s after launch</h2>
Using again but for 
:
(11)
(12)
<h2>d) Speed of the rocket 0.20 s after launch</h2>
We will use equation (2) remembering the rocket startted from rest:
(13)
(14)
Finally:
(15)
sodium is found in group one element, but flourine members of halogens . oxygen found in group six element ,but hydrogen found in group 1( according to periodic table)
