Answer:
3:00 - 3:02 and 3:07 - 3:08
Explanation:
Those are the only intervals in which Jenny's speed increased.
Answer:

Explanation:
From the question we are told that:
Resistor 
Voltage 
Capacitance of c_1 
Capacitance of c_2 
Time 
Generally the equation for charges is mathematically given by


Generally the equation for voltage across capacitors is mathematically given by




Generally the equation for charges is mathematically given by

Generally the equation for total charges
is mathematically given by


(a) 
First of all, we need to calculate the acceleration of the person, by using the following SUVAT equation:

where
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 1.00 cm = 0.01 m is the displacement of the person
Solving for a,

And the average force on the person is given by

with m = 75.0 kg being the mass of the person. Substituting,

where the negative sign means the force is opposite to the direction of motion of the person.
b) 
In this case,
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 15.00 cm = 0.15 m is the displacement of the person with the air bag
So the acceleration is

So the average force on the person is

The key is in "they lock together". This tells you this is a complete inelastic collision and therefore you can use the formula:
m1*v1+m2*v2=v(m1+m2)
Plug in numbers:
2000*3+2000*2=v(2000+2000)
so v=2 m/s, obviously in the same direction of motion in which they were both moving.
Answer
3.340J
Explanation;
Using the relation. Energy stored in capacitor = U = 7.72 J
U =(1/2)CV^2
C =(eo)A/d
C*d=(eo)A=constant
C2d2=C1d1
C2=C1d1/d2
The separation between the plates is 3.30mm . The separation is decreased to 1.45 mm.
Initial separation between the plates =d1= 3.30mm .
Final separation = d2 = 1.45 mm
(A) if the capacitor was disconnected from the potential source before the separation of the plates was changed, charge 'q' remains same
Energy=U =(1/2)q^2/C
U2C2 = U1C1
U2 =U1C1 /C2
U2 =U1d2/d1
Final energy = Uf = initial energy *d2/d1
Final energy = Uf =7.72*1.45/3.30
(A) Final energy = Uf = 3.340J