Answer:
The answer is 3.48 seconds
Explanation:
The kinematic equation
y= y0+V0*t+1/2*a*(t*t)
-50=0+(0)t+1/2(-9.8)*(t*t)
t=3.194 seconds
During ribbons ball,
x=x0+ Vt+1/2*a*(t*t)
x= 0+(15)*(3.194)+1/2*(0)* (3.194*3.194)
x= 47.9157m
So, distance (D) = 100-47.9157= 52.084m
52.084m=0+15(t)+1/2*(0)(t*t)
t=52.084/15=3.472286= 3.48seconds
A fan may be used to model an atom because the fan blades form something similar to a electron cloud. But there is really nothing to model the neutrons and protons. Also the fan is flat like where an atom is more 3-D sphere-like.
hope this helps
Ur welcome
have a great day (:
Answers:
a) 
b) derived
Explanation:
Density 
is a characteristic property of substances and materials and is defined as the relationship between the mass 
and volume 
of a specific substance or material, as shown below:
This means density is inversely proportional to volume.
In addition, density is a derived unit, because is based on two basic units of the International Sistem of Units: Mass (kilograms) and Volume (cubic meters)
