Aperson pushes a 18.8-kg shopping cart at a constant velocity for a distance of 17.9 m on a flat horizontal surface. she pushes in a direction 32.1 ° below the horizontal. a 52.7-n frictional force opposes the motion of the cart. (a) what is the magnitude of the force that the shopper exerts? determine the work done by (b) the pushing force, (c) the frictional force, and (d) the gravitational force.

a)  F = 62.2 N , b) W = 973.2 J , c)  W = -943.3 J  and d) W = 0 J

Explanation:

Work is a scalar that is obtained from the scalar product of two vectors, force and displacement.  the bold are vectors

          W = F.d = F d cos θ

a) As the car travels at constant speed the acceleration is zero

         Fx -fr = 0

         Fx = fr

        Cos θ = Fx / F

         F cos θ = fr

         F = fr / cos θ

         F = 52.7 / cos 32.1

         F = 62.2 N

Is the force exerted by the person

b) Let's calculate the thrust force jobs

         W = 62.2 17.9 cos 32.1

         W = 973.2 J

c) The force of friction that opposes the movement and is on the x-axis

          W = fr d cos 180

          W = 52.7 17.9 cos 180

          W = -943.3 J

d) The force of gravity that is vertical and has an angle of 90º with respect to the displacement

          W = mg d cos 90

          W = 0 J

quantum mechanics or quantum physics is physics of very small objects (particles) and physical entities.

quantum physics has some parallels to our macro world and some pretty unique ideas which theoretically and mathematically proven to be true even though we will never be able to access them because of our size.

there are many types of particles: subatomic, elementary etc.

subatomic means they are smaller than atom, elementary means they are at the very basis of everything.

subatomic particles are for eg. protons, neutrons but not electrons.

elementary particles are categorised into 3 groups by what they do.

these 3 groups are quarks, leptons and bosons.

light for example is a particle more precisely a photon a part of leptons.

proton (subatomic particle) is made out of 2 up quarks and 1 down quark each of these has a fractional charge like . (i crazy)

most famous scientist who contributed to this physics are:

the topic itself us understand a lot and will probably be vastly used in the future (quantum computers, understanding the big bang,

we also must not forget quantum effects like:

and there is more. but probably too much for this answer to be consistent due to my average understanding of this topic.

hope this you understand quantum mechanics a little more. i'm not an expert in the topic (so don't be like wth if you are an expert) but i'm very interested in it.

anyways quantum physics is a very hard topic (harder than physics (perhaps)) therefore searching for every information there is about it and learning it is unfortunately impossible (you can only specialise into 1 - 3 things or more (perhaps

have fun and i wish you luck!

r3t40

c. magnitude and direction