Physics Questions: Velocity, Acceleration, Laws of Motion, Waves, Magnetism, Current and Potential Difference

This article provides answers to various physics questions related to velocity, acceleration, laws of motion, waves, magnetism, current and potential difference. It explains the principles of conservation of energy, reflection, refraction, and total internal reflection with examples and illustrations.

PHYSICS QUESTIONS

TABLE OF CONTENTS
MAIN BODY..................................................................................................................................4
QUESTIONS...................................................................................................................................4
REFERENCES..............................................................................................................................22

MAIN BODY
QUESTIONS
1.1
Velocity define as the rate of change in the position which is respect to the reference frame and
time. velocity is identical to the provision of speed of objects and its motion direction.
Acceleration define as the rate in which the change of the velocity is done with respect to time
(Antonov, 2021).
VELOCITY ACCELERATION
Its nature is vector. It is also operate in vector nature.
Usually calculated with displacement Calculated with the velocity
Its formula and unit is displacement/time
And unit is meter per second (m/s).
Formula is velocity per time and unit is meter
per second square (m/s2)
Positive Generally negative
It generally ascertain that how rapidly the
object is moving and in what direction.
It ascertain as how quickly the velocity of the
object is changes within time.

Figure 1 velocity and acceleration
1.2

1st law of motion also considers as the “law of inertia” it states that when the body is at rest
or in a moving condition at the sustained speed in linear line, then it will keep in the rest or
moving position until and unless some external force act upon it.
example If ball is Rolling then it keep rolling until friction act upon it to stop it by external force
(Coelho, 2020).
Its implication is defining as object cannot begin, stop their direction by their own, it generally
requires the some force to act upon it. if cycle is moving suddenly if person stop paddling then
the cycle stop moving. It consists of the universe’s fundamental symmetry.
Figure 2 Law of inertia
2nd law of motion defines the connectivity between the object and acceleration. it states
that rate of time changes of body’s momentum is equivalent to the direction and magnitude of
the force which is imposed over it.
For an example if person is applying the force in pedalling then the cycle accelerated, as simply
by giving extra force to pedals it started moving fast.
Its implication is that acceleration only occurs when there is unbalanced force.

Figure 3 Second law of motion
3rd law of motion can be understood as if one object (X) is applying the force over other
object(Y), then it implies that Object(Y) also exert the force to the object (X). in simple aspect
for every action there is equal and opposite reaction (Anissofira and et.al 2017).
for example if stretching the elastic than it comes back to its original configuration.
Its implication shows the symmetry in the nature, also forces always appear in a pair.
Figure 4 Third law of motion

2.2
The principle of conservation of energy states that the energy of an isolated system remains
conserved. It means that energy can neither be created, nor be destroyed, it can only be
transformed from one form to another. For example, when a pendulum is made to swung in
upward direction, the kinetic energy possessed by the pendulum, by the virtue of its motion, gets
converted into potential energy. Such that the total energy of the system is constant and equal to
the sum of kinetic energy and potential energy. When the pendulum is at its extreme end, it stops
for a while. The kinetic energy at this point is zero and the total energy of the system is equal to
the potential energy. Therefore, the total energy of this system is remaining constant as the
pendulum swings (Raissi, Perdikaris and Karniadakis, 2017). The energy is only getting
transformed into different forms, i.e, potential energy and kinetic energy.
Illust
ration 1: Principle of Conservation of Energy

2.3
For a moving object, its momentum is equal to the product of its mass and its velocity.
Momentum is a vector quantity, that means it possess both magnitude and direction. The total
momentum of isolated systems remains constant. For a system, consisting of several objects, the
total momentum is the sum of momenta of all the individual objects.
For instance, when a bullet is fired from a gun, the gun recoils in the opposite direction. This is
because of the law of conservation of momentum. Initially, both gun and the bullet inside the
gun, is at rest and the total momentum of the system is zero (Handhika, Cari and Suparmi,
2017). When the bullet is fired from the gun, it gains momentum. But the net momentum must
remain zero. So the gun gains an equal and opposite momentum to cancel out the momentum of
the bullet and it recoils backward.
Similarly, during a rocket launch, due to the downward thrust of the gases, the rocket gains a
momentum in the upward direction and that is how it is able to fly in the up.
Another example could be that of an inflated balloon. Initially it is at rest, but as soon as air
escapes out of it, the balloon gains momentum and flies forward.
Illustration 2: Conservation of momentum

3.1
There are mainly three terms that are used to describe a wave: wavelength, frequency and
amplitude.
The amplitude of a wave is the height of the wave and it is equal to half of the distance between
the highest point (crest) and the lowest point (trough). The SI unit of amplitude is metre (m).
Wavelength is the distance between two crests or two trough. The SI unit of wavelength is metre
(m). Wavelength and frequency are indirectly proportional. Frequency is measured as the
number of waves that pass through a point in a given time period (Bejan and Errera, 2017).
Frequency is expressed in hertz (Hz).
Other terms associated with a wave are: Time period, Peak and Trough. Time period is the time
taken by the wave to complete one cycle. It is measure in seconds (s). It is inversely proportional
to Frequency. Peak is the highest point of the wave, while Trough is the lowest point of the
wave.

3.2
A wave is a disturbance through which energy moves from one place to another without any
movement of matter. When a longitudinal wave propagates, the medium through the wave is

travelling, moves in the same direction as the wave. Whereas when a transverse wave
propagates, the medium moves perpendicular to the direction in which the wave is travelling.
The longitudinal wave makes compressions and rarefactions when it travels. The entire motion is
in one dimension. The transverse wave makes crests and troughs while travelling. The motion is
two-dimensional. Longitudinal waves can travel in any medium, but transverse waves can only
travel through solid and liquid media. Examples of longitudinal and transverse waves are sound
waves and S waves produced during an earthquake.
3.3
When sound waves reach the interface of two mediums, some part of the wave is reflected, while
the other is transmitted into the second medium. The reflected sound waves follow the laws of
reflection. The sound wave that is transmitted, undergoes refraction. Water waves refract when
they move from deep water to shallow water.
Diffraction happens when waves change their direction while encountering an obstacle or
passing through an opening (Yuliati, Yogismawati and Nisa, 2018). Diffraction of sound waves
happens when sound waves bend around the corners and that is why someone speaking in the
adjacent room can be heard. Water waves too, diffract when they encounter a gap or an obstacle.
The waves after diffraction propagate at a different angle.
4.1
The two laws of reflection are: One, the angle of the reflected ray with normal is equal to the
angle of incidence made by the incident ray with the normal, i.e. angle i = angle r. Two, the
reflected ray, the incident ray and the normal to the surface of the reflecting surface, all lie in the
same plane.
The application of the law of reflection can be seen in meters like ammeters and voltmeters
which use a mirror to avoid parallax error. A microscope takes use of a mirror under the
specimen to reflect the light to the specimen. An overhead projector reflects light towards the
screen. Parabolic mirrors which are used as reflectors in torches and car headlights, also use law

of reflection. Other examples are concave mirrors that are used as shaving mirrors and convex
mirrors that are used as rear view mirrors.

4.2
The two laws of refraction are: One, the incident ray, the refracted and the normal to the
interface that is between the two mediums, all lie in the same plane. Two, the ratio of the sine of
the angle of incidence to the sine of the angle of refraction is a constant, if the conditions such as
the colour of the wave and the two media are to remain the same. This second law is also known

as Snell's law of refraction and the constant is called the refractive index of the second media
with respect to the first media.
Sine of angle i / sine of angle r = constant

4.3
The two conditions that are necessary for total internal reflection to occur are: One, light should
be travelling from an optically denser medium to an optically lighter medium. Second, the angle
of incidence should be greater than the critical angle. The value of the critical angle will depend
on the refractive indices of the two media.
The most common application of total internal reflection is in optical fibres. Optical fibres are
used for long distance communication. The information is relayed in the form of a light wave.
The light wave travels inside the fibre by continuously reflecting in the fibre cable, making use
of TIR property of the material (Pervan and Murphey, 2019).
5.1
Magnetism define as the attraction or repulsion force which is mainly because of the
electron’s arrangement. it states that every magnet has its poles, and these poles can be
recognised when their direction at certain point is suspended. Therefore, the direction can be
from north pole to south pole.
Law of magnetism are-
1. Same magnetic poles repel each other as the force lines are present in the different
direction.
For example: If one pole is south and other is also than repulsion takes place.

Figure 5 Repulsion
2. Opposite poles attract each other, as if the two sides are different which is one is north
and other is south than in between attraction takes place.
Figure 6 Attraction
5.2

Magnetic field can be defining as when there is availability of the magnetic influence, in this
the magnetic area direction can be present by the magnetism line forces. The possible rules for
drawing the magnetic line are-
 Field must be deviated to the magnetic line forces.
 There should be no overlap between the field lines.
 As the magnetism area across the bar magnet arrives through the poles and discontinues
at the different pole.
Figure 7 Magnetic field around the bar magnet
When a current flow across the wire, in such it develops the magnetic field circularly around
wire. in the magnetic field which is developed by the current it results as changes in direction
(Suleiman, 2018).

Figure 8 Magnetic field across the current carrying wire
Magnetic field for the solenoid is completely proportional with respect to the current and
rotation of the turns per length. direction of the field can be deduced by the using the second
right hand rule. In which the magnetic field that it generated by the current in a linear wire, it
role around the ring.

Figure 9 Magnetic field across solenoid
5.3
Current define as the flow of charges and it is mainly calculated in a component, it only exists
when there is flow charge is available in that region. Its Unit can be defining as Ampere. For the
series in which common current is flow throughout the circuit, but in parallel there is different
quantity of the current flows through every parallel point of circuit.

Figure 10 Electric current
Potential difference defines as the complete energy which is being utilised in between the two
points. As for the potential difference the voltage across the parallel circuit are common and
same, but in series it does not remain same (Kossovsky, 2020).

Figure 11 Potential difference

REFERENCES
Books and Journals
Anissofira, A. and et.al 2017, September. Newton’s cradle experiment using video tracking
analysis with multiple representation approach. In Journal of Physics: Conference
Series (Vol. 895, No. 1, p. 012107). IOP Publishing.
Antonov, A.A., 2021. Special theory of relativity, which is studied in physics textbooks, is
incorrect. Deutsche Internationale Zeitschrift für zeitgenössische Wissenschaft. (16).
pp.49-53.
Bejan, A. and Errera, M.R., 2017. Wealth inequality: The physics basis. Journal of Applied
Physics. 121(12). p.124903.
Coelho, R.L., 2020. A Comment on Solari and Natiello’s Constructivist View of Newton’s
Mechanics. Foundations of Science, pp.1-8.
Handhika, J., Cari, C. and Suparmi, A., 2017. Students’ representation about Newton law:
consequences of “zero intuition”. In Journal of Physics: Conference Series (Vol. 795, No.
1, p. 012057). IOP Publishing.
Kossovsky, A.E., 2020. Newton’s Three Laws of Motion. In The Birth of Science (pp. 169-169).
Springer, Cham.
Pervan, A. and Murphey, T., 2019. Algorithmic materials: Embedding computation within
material properties for autonomy. In Robotic Systems and Autonomous Platforms (pp.
197-221). Woodhead Publishing.
Raissi, M., Perdikaris, P. and Karniadakis, G.E., 2017. Physics informed deep learning (part i):
Data-driven solutions of nonlinear partial differential equations. arXiv preprint
arXiv:1711.10561.
Suleiman, R., 2018. Newton’s first law revisited. Journal of Modern Physics,(forthcoming).
Yuliati, L., Yogismawati, F. and Nisa, I.K., 2018, September. Building scientific literacy and
concept achievement of physics through inquiry-based learning for STEM education.
In Journal of Physics: Conference Series (Vol. 1097, No. 1, p. 012022). IOP Publishing.
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