Atmospheric pressure is caused by the weight of the atmosphere pushing down on itself and on the surface below it.
Pressure is defined as the force acting on an object divided by the area upon witch the force is acting.
Density =mass/volume
density= (0.044kg/(11 x10^-6)
4000kg/m^3
Hello there!
I hope you and your family are staying safe and healthy during this unprecendented time.
A) What is the work done?
Answer: We need to use the formula



B) What is the work done on the cart by the gravitational force?
Alright, we know that the gravitional force is perpendicular to the diplacement. Therefore, we gonna use the following formula:


C) What is the work done on the cart by the shopper?
This is the easier part, since we already know that the work done by the shopper is the same as the work done by the friction force

D) Find the force the shopper exerts, using energy considerations.

E) What is the total work done?
You just need to add them:

To develop the problem it is necessary to apply the kinematic equations for the description of the position, speed and acceleration.
In turn, we will resort to the application of Newton's second law.
PART A) For the first part we look for the time, in a constant acceleration, knowing the speeds and the displacement therefore we know that,

Where,
X = Desplazamiento
V = Velocity
t = Time
In this case there is no initial displacement or initial velocity, therefore

Clearing for time,



PART B) This is a question about the impulse of bodies, where we turn to Newton's second law, because:
F = ma
Where,
m=mass
a = acceleration
Acceleration can also be written as,

Then





Negative symbol is because the force is opposite of the direction of moton.
PART C) Acceleration through kinematics equation is defined as




The gravity is equal to 0.8, then the acceleration is


Desireurban has given a good discussion in the first answer,
but be careful with it:
-- Yes, skimming instead of reading carefully can be non-productive.
-- Using credible sources is MORE productive, and using less reliable sources
can be LESS productive.
Another nonproductive learning behavior ... one that I worry about a lot ...
is slapping the question up on Brainly and waiting for someone to give
you the answer, instead of taking some time to think about it.