Any substance that contains starch turns blue-black in presence of <u>iodine solution.</u>
 
 
        
             
        
        
        
As Potential energy =mgh 
m= 0.95kg
h=3 meter
g = 9.8 m/sec^2. ( acceleration due to gravity) 
So P.E =(0.95)(9.8)(3)kgm^2/s^2
P.E =27.93 joules 
 
        
             
        
        
        
The object takes 0.5 seconds to complete one rotation, so its rotational speed is 1/0.5 rot/s = 2 rot/s.
Convert this to linear speed; for each rotation, the object travels a distance equal to the circumference of its path, or 2<em>π</em> (1.2 m) = 2.4<em>π</em> m ≈ 7.5 m, so that
2 rot/s = (2 rot/s) • (2.4<em>π</em> m/rot) = 4.8<em>π</em> m/s ≈ 15 m/s
thus giving it a centripetal acceleration of
<em>a</em> = (4.8<em>π</em> m/s)² / (1.2 m) ≈ 190 m/s².
Then the tension in the rope is
<em>T</em> = (50 kg) <em>a</em> ≈ 9500 N.
 
        
             
        
        
        
Axial Tilt and Sun Energy
 This axial tilt means that during the Earth's journey around the sun the poles receive varying amounts of sunlight. The equator, however, receives relatively consistent sunlight all year. The consistency of energy means the equator's temperature stays relatively constant all year.
        
             
        
        
        
Using Newton's Second Law, we can find the air resistance. We know the net force is equal to mass times acceleration.
