Answer:20 minutes
Explanation:
06:58am - 06:38am =20 minutes
So that we do not contaminate it with microorganisms or garbage or other human stuff.
Answer:

Explanation:
From the question we are told that:
Crane Length 
Crane Mass 
Arm extension at lifting end 
Arm extension at counter weight end 
Load 
Generally the equation for Torque Balance is mathematically given by



Answer:
I got you.. i'm in middle school and had that same question.
Explanation:
Refer to the diagram shown below.
The vertical distance traveled is
s = 25 m
The initial vertical launch velocity is zero.
Therefore
s = (1/2)*g*t²
where g = 9.8 m/s²
t = the time of flight, s
That is,
0.5*9.8*t² = 25
t² = 25/4.9 = 5.102
t = 2.26 s
Answer: 2.26 s