Tuberculosis. Reason: I just took the test and got it right
        
             
        
        
        
Answer: the golf ball with smooth surface would hit the ground first.
Jusitification:
An analysis of forces show two vertical forces acting on the golf balls.
1) one force is the weight (mg) which is vertical downward
2) the other force is the drag force exerted by the air on the golf balls, and it is vertical upward.
3) the drag force opposes the weight, so the acceleration downward is determined by the difference of the weiight and the drag force, until the balls reach the terminal speed (when the drag force equals the weight).
4) the drag force depends on the shape and area of the object falling. Being the surface of one ball smooth implies that the drag force will be less than the one on the other ball.
5) less drag force implies that the terminal velocity of the smooth ball will he higher, ant then it will hit the ground first.
 
        
             
        
        
        
Answer:
12.5N
Explanation:
From newton law of universal gravitation F= GmM/d2.
that means Force is inversely proportional to the square of the distance apart.
F1= 50N, d1=6400km
F2=?, d2=12800km
F1/F2=d2×d2/d1×d1 so we have 50/F2= 12800×12800/6400×6400...F2=6400×6400×50/(12800×12800)=12.5N
 
        
             
        
        
        
Answer: 6.64 × 10^ -6 m
Explanation:
for a constructive interference; 
ρ= 2πm 
remember that we are looking for the seventh bright side fringe. 
so, m=7 
ρ=14π 
We now have to find the phase different 
ρ`=2πx/ρ - 2πx/ρ
p` is the wavelenght in the mica. x= width of the mica wavelength in the mica.
ρ= ρ/n.
n= refractive index.
The phase will now be 
ρ`= 2πx/ρ - 2πx = 2πx(n-1)/ρ.
ρ= ρ`
14π = 2πx (n-1)/ ρ
we now solve for x; x = 7ρ/n-1
x = 7(550× 20^ 9)/ 1.58 - 1
= 6.64 × 10^-6