Answer:
<em>The force required is 3,104 N</em>
Explanation:
<u>Force</u>
According to the second Newton's law, the net force exerted by an external agent on an object of mass m is:
F = ma
Where a is the acceleration of the object.
On the other hand, the equations of the Kinematics describe the motion of the object by the equation:

Where:
vf is the final speed
vo is the initial speed
a is the acceleration
t is the time
Solving for a:

We are given the initial speed as vo=20.4 m/s, the final speed as vf=0 (at rest), and the time taken to stop the car as t=7.4 s. The acceleration is:


The acceleration is negative because the car is braking (losing speed). Now compute the force exerted on the car of mass m=1,126 kg:

F= 3,104 N
The force required is 3,104 N
Answer:
The charge on the dust particle is 
Explanation:
From the question we are told that
The length is 
The width is 
The charge is 
The mass suspended in mid-air is 
Generally the electric field on the carpet is mathematically represented as

Where
is the permittivity of free space with value 
substituting values


Generally the electric force keeping the dust particle on the air equal to the force of gravity acting on the particles

=> 
=> 
=> 
=> 
Another (slightly more technical) name for kidney stones is "renal calculus".
I know this because we have met many times, and we are old friends.