Answer: R = 394.36ohm
Explanation: In a LR circuit, voltage for a resistor in function of time is given by:

ε is emf
L is indutance of inductor
R is resistance of resistor
After 4s, emf = 0.8*19, so:





R = 394.36
In this LR circuit, the resistance of the resistor is 394.36ohms.
Answer:
تكون دائمًا متعامدة مع سرعة الجسم وتكون دائمًا في اتجاه مركز انحناء المسار
Explanation:
Answer:
A free body diagram with 2 forces: the first pointing downward labeled F Subscript g Baseline 20 N and the second pointing upward labeled F Subscript air Baseline 20 N.
Explanation:
This is because at terminal velocity, the ball stops accelerating and the net force on the ball is zero. For the net force to be zero, equal and opposite forces must act on the ball, so that their resultant force is zero. That is F₁ + F₂ = 0 ⇒ F₁ = -F₂
Since F₁ = 20 N, then F₂ = -F₁ = -20 N
So, if F₁ points upwards since it is positive, then F₂ points downwards since it is negative.
So, a free body diagram with 2 forces: the first pointing downward labeled F Subscript g Baseline 20 N and the second pointing upward labeled F Subscript air Baseline 20 N best describes the ball falling at terminal velocity.
Answer:
70509.8039216 N/C
Explanation:
k = Coulomb constant = 
q = Charge = 2.00 µC
l = Length of filament = 5.1 m
r = Radius of cylinder = 10 cm

Electric field is given by

The electric field at the surface of the cylinder is 70509.8039216 N/C