Humid air has higher pressure because of the heaviness of the water
Answer:
7.45 s.
Explanation:
Given:
h = 68.1 m
vi = 0 m/s
vf = 42.4 m/s
g = 9.81 m/s^2
Using,
h = vi*t +1/2*(a*t^2)
68.1 = 1/2 * (9.81*t^2)
t = sqrt((68.1*2)/9.81)
= 3.726 s.
Total time of flight = 2*t
= 2 * 3.726
= 7.45 s.
With acceleration

and initial velocity

the velocity at time <em>t</em> (b) is given by




We can get the position at time <em>t</em> (a) by integrating the velocity:

The particle starts at the origin, so
.



Get the coordinates at <em>t</em> = 8.00 s by evaluating
at this time:


so the particle is located at (<em>x</em>, <em>y</em>) = (64.0, 64.0).
Get the speed at <em>t</em> = 8.00 s by evaluating
at the same time:


This is the <em>velocity</em> at <em>t</em> = 8.00 s. Get the <em>speed</em> by computing the magnitude of this vector:

It's simple.
We know force is the rate of change in momentum.
So F=(mv-mu)/t or F=m(v-u)/t
=1200*(25-10)/5=3600N