The punching bag applies the same amount of force to the boxer’s hand. (C)
Explanation:
It is given that,
Electric field strength, E = 20,000 N/C
Spacing between parallel-plate capacitor, d = 1 mm = 0.001 m
Initial velocity of electron, u = 0
Let v is the electron’s speed when it reaches the positive plate. The force acting on the electron is :

Also, 



Using third equation of motion as :



v = 2649528.2599 m/s
or

So, the velocity of the electron when it reaches the positive plate is
. Hence, this is the required solution.
Answer:
v=2.45 m/s
Explanation:
The rotational kinetic energy is calculated with:

The moment of inertia of a disk is:

A point on the rim of a disk will have a speed of:

Putting all together:

Which for our values is:

Answer
given,
time = 10 s
ship's speed = 5 Km/h
F = m a
a is the acceleration and m is mass.
In the first case
F₁=m x a₁
where a₁ = difference in velocity / time
F₁ is constant acceleration is also a constant.
Δv₁ = 5 x 0.278
Δv₁ = 1.39 m/s

a₁ = 0.139 m/s²
F₂ =m x a₂
F₃ = F₂ + F₁
Δv₃ = 19 x 0.278
Δv₃ = 5.282 m/s
a₃=Δv₂ / t

a₃ = 0.5282 m²/s
m a₃=m a₁ + m a₂
a₃ = a₂ + a₁
0.5282 = a₂ + 0.139
a₂=0.3892 m²/s
F₂ = m x 0.3892...........(1)
F₁ = m x 0.139...............(2)
F₂/F₁
ratio = 
ratio = 2.8