Answer:
1. 
2. 
Explanation:
Radial acceleration is:
(1)
With r the radius respects the axis of rotation and v the tangential velocity that is related with angular velocity (ω) by:
(2)
By (2) on (1):


To find the acceleration of the tube with the fall, we can use the expression:
(3)
Due impulse-momentum theorem:
(4)
with p the momentum and J the impulse. By (4) on (3):

And using Newton's second law (F=ma) and that (P=mv):
(5)
Final velocity is the velocity just after the encounter with hard floor, and initial momentum us just before that moment so the first one is zero and the second one can be found sing conservation of energy:

So (5) is:

solving for a:
It’s negative because is opposed to the tube movement.
Answer:
0.68 seconds
Explanation:
Data provided in the question:
Mass of the box = 50 kg
Speed of the box = 1.0 m/s
Coefficient of friction, μ = 0.15
Now,
Force applied = μmg
Here,
g is the acceleration due to gravity = 9.8 m/s²
Thus,
F = 0.15 × 50 × 9.8
= 73.5 N
Also,
Force = Mass × Acceleration
thus,
73.5 N = 50 × a
or
a = 1.47 m/s²
After doubling the speed
Final speed = 2 × Initial speed
= 2 × 1 m/s
= 2 m/s
Also,
Acceleration = [change in speed] ÷ Time
or
1.47 = [ 2 - 1 ] ÷ Time
or
Time = 1 ÷ 1.47
or
Time = 0.68 seconds
I think 4.69 x 108 charges have been removed
Helium lithium and calcium