Heat due to the amount of density difference within a fluid
        
             
        
        
        
Answer:
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
Explanation:
The spoon is a curved metallic object, when we see ourselves from the back we have a convex mirror, in this type of mirror when the law of reflection is applied the rays diverge therefore the eye-brain system forms the image with the prolongation of the rays, therefore the image is straight and smaller than the object.
When we look through the deep side of the spoon, we have a concave mirror and as the object (we) is further away than the distance, the rays converge to a point, so the image is real, inverted smaller than the object.
In summary.
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
 
        
             
        
        
        
A reference point would be something not on the ship which could be used to calculate distance traveled.
Answer: C.) A lighthouse on a nearby Island
 
        
                    
             
        
        
        
Two half lives so it is 4000 years old
        
                    
             
        
        
        
Answer:
C. 30.6m
Explanation:
To find the height of the tower, we are to use Newtons law of motion to solve this problem. Since the penny is falling from the top of the tower, it is acted by the acceleration due to gravity. The formula to be used is:

Where H is the height of the tower, t is the time taken to hit the ground, u is the initial velocity and g is the acceleration due to gravity. 
Given that, t = 2.5 s, g =9.8 m/s², u = 0 m/s (at the top of tower)
