Answer:
The value is 
Explanation:
From the question we are told that
The speed of in a vacuum is 
The speed of light in the material is 
Generally the reflection of the material is mathematically represented as

=> 
=> 
Given: v0= 18.0 m/s, y0=0m, yf=11m, g=-9.81 m/s^2
v0= initial velocity, vf= final velocity, y0= initial height, yf= final height, g= gravity, sqrt()= square root, ^2=squared
vf^2=v0^2 + (2)(g)(yf-y0)
vf^2=(18.0 m/s)^2+(2)(-9.81 m/s^2)(11 m-0m)
vf^2=18.0 m/s)^2 + (-19.62 m/s^2)(11 m)
vf^2=(324 m^2/s^2) - (215.82 m^2/s^2)
vf^2=108.18 m^2/s^2
vf=sqrt(108.18 m^2/s^2)
vf=10.4 m/s
Hello!!
For calculate the work let's applicate the formula:


W = Work = ?
F = Force = 1525 N
d = Distance = 381 m
⇒ 
W = 1525 N * 381 m
⇒ 
W = 581025 J

Answer:
a constabt force that acts on object that rub together
Explanation:
It is because Friction is the rubbing of one body against another body