1. describe two important ways in which weight and mass differ and one important way in which they are related. 2. according to newton’s first law, if no force acts on an object, it will just continue moving. explain in terms of newton’s first law why a car engine must exert a force between the car and the road to drive at a constant speed on a straight and level road.

1).  Weight and mass are different.
. . . . . Mass is a property of the person or thing and doesn't depend
on anything else.  Weight depends on what else is in the neighborhood.
. . . . . Mass never changes, no matter where the person or thing goes.
Weight changes, depending on what else is in the neighborhood. 

Weight and mass are related:
. . . . . Weight is the mass of the person or thing multiplied by the gravity
in the place where the mass is.  So as long as you stay in the same place,
weight and mass are directly connected.  If you know either the mass or the
weight, AND you know the gravity in the place where the mass is, you can
always calculate exactly what the other number is.

2).  According to Newton’s first law, if no force acts on an object, it will
just continue moving.  But we NEVER see this in our daily life on Earth.
In everything that we see, if no force acts on a moving object, it stops !
For example, a car engine must exert a force between the car and the road
to keep the car moving at a constant speed on a straight and level road.

The reason is that whenever we see anything moving, there is ALWAYS
a force on it that's trying to make it stop moving.  Always !  That force is
the result of friction.

-- A rolling ball stops rolling.  Either there's friction between the ball
and the dirt, or between the ball and the concrete, or the ball has to
keep pushing blades of grass out of the way so it can roll through.

-- A bullet shot from a gun slows down and stops.  It has to keep pushing
air molecules out of the way so it can sail through.

-- Even if the road is straight and level, a car slows down and stops if you
don't give it some gas to keep it going.
There is friction between the tires and the road that slows the car down.
AND the car also has to keep pushing air molecules out of the way so that
it can sail through.

On Earth in our daily life, we NEVER see anything moving that DOESN't
have forces acting on it trying to make it stop.  If we could see such a
thing, then the object would just keep going and never stop.  This can
happen in outer space, where there's no concrete, no blades of grass,
and no air molecules.

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:

max planckalbert einsteinerwin schrödingermany

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:

superposition (where 1 thing can be this and that at the same time),entanglement (where two particles are seemingly connected by some sort of unknown (or known) force, energy, matter (i know all that can be the same at least it was at the beginning)

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

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.