Centripetal force = (mass) x (speed)² / (radius)
= (20 kg) x (20 m/s)² / (20 m)
= (20 x 20 / 20) (kg-meter/sec²)
= 20 newtons
Answer:
1. The current will drop to half of its original value.
Explanation:
The problem can be solved by using Ohm's law:

where
V is the voltage across the circuit
R is the resistance of the circuit
I is the current
We can rewrite it as

In this problem, we have:
- the resistance of the circuit remains the same: R' = R
- the voltage is decreased to half of its original value: 
So, the new current will be

so, the current will drop to half of its original value.
Answer:
a) 4.9*10^-6
b) 5.71*10^-15
Explanation:
Given
current, I = 3.8*10^-10A
Diameter, D = 2.5mm
n = 8.49*10^28
The equation for current density and speed drift is
J = I/A = (ne) Vd
A = πD²/4
A = π*0.0025²/4
A = π*6.25*10^-6/4
A = 4.9*10^-6
Now,
J = I/A
J = 3.8*10^-10/4.9*10^-6
J = 7.76*10^-5
Electron drift speed is
J = (ne) Vd
Vd = J/(ne)
Vd = 7.76*10^-5/(8.49*10^28)*(1.60*10^-19)
Vd = 7.76*10^-5/1.3584*10^10
Vd = 5.71*10^-15
Therefore, the current density and speed drift are 4.9*10^-6
And 5.71*10^-15 respectively