Answer:
Option b. is correct.
Explanation:
In the given question a parachutist is falling toward the ground .
Also, the downward force of gravity is exactly equal to the upward force of air resistance.
So, net force applied to the parachutist is equal to zero ( because both force acts in opposite direction ).
Now by first law of motion :
An object will be in rest or in constant speed unless and until no external force is applied on it .
So, in the question the velocity of the parachutist is not changing with time.
Therefore, option b. is correct.
Hence, this is the required solution.
I would say friction because it requires to surfaces in order for the force to take place
correct me if I'm wrong.
Answer:
3×10^-12 C
Explanation:
The total of the three charges is ...
(-3 +8 +4)×10^-12 C = 9×10^-12 C
Assuming the charge is equally distributed between the balls when they are brought in contact, the charge on each ball will be ...
(9/3)×10^-12 C = 3×10^-12 C
Answer:
r2 = 1 m
therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m
Explanation:
For this exercise we must use conservation of energy
the electric potential energy is
U =
for the proton at x = -1 m
U₁ =
for the electron at x = 1 m
U₂ =
starting point.
Em₀ = K + U₁ + U₂
Em₀ =
final point
Em_f =
energy is conserved
Em₀ = Em_f
\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e^2 (- \frac{1}{r_2 +1} + \frac{1}{r_2 -1})
\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e²(
)
we substitute the values
½ 9.1 10⁻³¹ 450 + 9 10⁹ (1.6 10⁻¹⁹)² [
) = 9 109 (1.6 10-19) ²(
)
2.0475 10⁻²⁸ + 2.304 10⁻³⁷ (5.0125 10⁻³) = 4.608 10⁻³⁷ (
)
2.0475 10⁻²⁸ + 1.1549 10⁻³⁹ = 4.608 10⁻³⁷
r₂² -1 = (4.443 10⁸)⁻¹
r2 =
r2 = 1 m
therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m