Explanation:
speed of light= c
wave length= L
frequency= f
c=Lf → L= c/f → L= 3 × 10⁸/ 27 × 10⁹ → L = 1/90 ≈ 0.011 m
 
        
             
        
        
        
When Emmett is lifting a box
vertically, the forces that must be added to calculate the total force are: the
gravitational force, tension force(the force exerted by Emmett to the box and
the force exerted by the box to Emmett), and air resistance force.
 
        
             
        
        
        
Answer:
You know the saying "Opposites attract" well that is how you can remember that South and North Magnetic Poles connect.  
Explanation:
Hope this helps ya
 
        
             
        
        
        
Answer:
The First State Was Delaware. Delaware was made a state in December 7, 1787. It was made a state a week before Pennsylvania. 
Give Brainliest if you please
 
        
             
        
        
        
 Answer:
A. The melting of ice is both a desirable and undesirable change because, ice is needed to melt so as to make liquid water available for animal and plant use and consumption and also to release the energy used in the fusion process of ice formation. Melting of ice is undesirable because melting ice liberate water slowly, and the water liberated can erode surface soil. Melting ice reduces the available heat sink on earth and also reduces the available stored up fresh water supply on earth. 
B. The appearance of hailey comet once every 72 year is a periodic change because it's motion around the solar system is repeated with time. The reason for this highly elliptical and eccentric path of motion is largely due to the gravitational effect of the sun and the planets on the comet.