#2
As it is given here
initial speed is

After 4 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 2 m/s^2 rate.
#3
As it is given here
initial it starts from rest

After 2.5 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 6 m/s^2 rate.
#4
i think question is not correct as in first line it is saying about a bag of trash and then in next line it is asking for the position of Jumper and bridge.
They actually DO have velocity limits. There are legal restrictions on both speed and direction.
-- Speeds are limited according to the black numbers on white signs that you see on sign-posts everywhere.
-- Directions are limited by the layout of the pavement and curbs on all the highways, avenues, roads, boulevards and streets, as well as the countless signs that say "One Way", "No Left Turn", "Keep Right", "Keep Left", etc. Violate one of these, and you get nailed as sure as if you had exceeded a posted speed limit.
Answer:

Explanation:
<u>Capacitance</u>
A two parallel-plate capacitor has a capacitance of

where

A = area of the plates = 
d = separation of the plates

We need to compute C. We'll use the circuit parameters for that. The reactance of a capacitor is given by

where w is the angular frequency

Solving for C

The reactance can be found knowing the total impedance of the circuit:

Where R is the resistance,
. Solving for Xc

The magnitude of the impedance is computed as the ratio of the rms voltage and rms current

The rms current is the peak current Ip divided by
, thus


Now collect formulas

Or, equivalently



The capacitance is now

The radius of the plates is

The separation between the plates is


