Answer:12.8 ft/s
Explanation:
Given
Speed of hoop
height of top
Initial energy at bottom is
Where m=mass of hoop
I=moment of inertia of hoop
=angular velocity
for pure rolling
Energy required to reach at top
Thus 512.2 m is converted energy is spent to raise the potential energy of hoop and remaining is in the form of kinetic and rotational energy
Therefore
Answer:
Diffusion time is 7.42 h
Solution:
As per the question:
Temperature, T =
Surface concentration of arsenic,
Surface concentration below Silicon surface,
D =
x =
Initial concentration at t = 0,
Now, by using Flick's second eqn:
Thus by putting appropriate values:
(1)
Now,
Now, from error function values tabulation:
For z = 2.0, erf(z) = 0.998
For z = 2.2, erf(z) = 0.995
Now,
With the help of linear interpolation method:
z = 2.12
Now, using eqn (1) and above value:
= 26700 s
t =