Everything Physics

Question 1

Normal Force

Answer 1

the force or the component of a force which a surface exerts on an object with which it is in contact, and which is perpendicular to the surface

Question 2

Friction Force

Answer 2

the force that opposes the motion of an object and which acts parallel to the surface

Question 3

Static Friction Force

Answer 3

the force that opposes the tendency of motion of a stationary object relative to a surface

Question 4

Kinetic Friction Force

Answer 4

the force that opposes the motion of a moving object relative to a surface

Question 5

Newton 1

Answer 5

a body will remain in its state of rest or motion at constant velocity unless a non-zero resultant/net force acts on it

Question 6

Newton 2

Answer 6

when a resultant/net force acts on an object, the object will accelerate in the direction of the force at an acceleration directly proportional to the force and inversely proportional to the mass of the object

Question 7

Newton 3

Answer 7

when object A exerts a force on object B, object B SIMULTANEOUSLY exerts an oppositely directed force of equal magnitude on object A

Question 8

Newton Universal Gravitation

Answer 8

each body in the universe attracts every other body with a force that is directly
proportional to the product of their masses and inversely proportional to the square of the distance between their centres

Question 9

Weight

Answer 9

the gravitational force the Earth exerts on any object on or near its surface

Question 10

Momentum

Answer 10

the product of an object’s mass and its velocity

Question 11

Linear Momentum

Answer 11

a vector quantity with the same direction as the velocity of the object

Question 12

Newton 2 with regards to momentum

Answer 12

the net force acting on an object is equal to the rate of change of momentum
of the object in the direction of the resultant/net force

Question 13

Impulse

Answer 13

the product of the resultant/net force acting on an object and the time the resultant/net force acts on the object. It is a
vector quantity

Question 14

Isolated System

Answer 14

a system on which the resultant/net external force is zero. An isolated system excludes external forces that originate outside the colliding bodies, e.g. friction. Only internal forces, e.g. contact forces between the colliding
objects, are considered

Question 15

Principle of conservation of linear momentum

Answer 15

the total linear momentum of an isolated system remains constant (is
conserved)

Question 16

Projectile

Answer 16

an object which has been given an initial velocity and then moves under the influence of the gravitational force only

Question 17

Free fall

Answer 17

motion during which the only force acting on an object is the gravitational force

Question 18

Work done by object with constant force F

Answer 18

is FΔxcosθ , where F is the magnitude of the force, Δx the magnitude of the
displacement and θ the angle between the force and the displacement

Question 19

Work-Energy theorem

Answer 19

The work done on an object by a net force is equal to the change in the object’s kinetic energy OR the work done on an object by a net force is equal to the change in the object’s kinetic energy. (Wnet = ΔK = Kf - Ki)

Question 20

Conservative Force

Answer 20

is a force for which the work done in moving an object between two points is independent of the path taken

Question 21

Non-conservative Force

Answer 21

is a force for which the work done in moving an object between two points depends on the path taken

Question 22

Principle of conservation of mechanical energy

Answer 22

the total mechanical energy (sum of gravitational potential energy and
kinetic energy) in an isolated system remains constant

Question 23

Power

Answer 23

is the rate at which work is done or energy is expended

Question 24

Doppler Effect

Answer 24

the change in frequency (or pitch) of the sound detected by a listener, because the sound source and the listener have different velocities relative to the medium of sound propagation

Question 25

Coulomb's law

Answer 25

the magnitude of the electrostatic force exerted by one point charge (Q1) on another point charge (Q2) is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance (r) between them

Question 26

Electric Field

Answer 26

a region of space in which an electric charge experiences a force. The direction of the electric field at a point is the direction that a positive test charge would move if placed at that point

Question 27

Electric field at a point

Answer 27

The electric field at a point is the electrostatic force experienced per unit positive charge placed at that point

Question 28

Ohms law

Answer 28

the potential difference across a conductor is directly proportional to the current in the conductor at constant temperature

Question 29

EMF

Answer 29

the maximum energy provided by a battery per unit charge passing through it

Question 30

RMS value

Answer 30

the DC potential difference/current which dissipates the same amount of energy as AC

Question 31

RMS potential difference

Answer 31

the AC potential difference which dissipates/produces the same amount of energy as an equivalent DC potential difference.

Question 32

RMS current

Answer 32

the alternating current which dissipates/produces the same amount of energy as an equivalent direct current (DC).

Question 33

Photoelectric effect

Answer 33

the process whereby electrons are ejected from a metal surface when light of suitable frequency is incident on that surface

Question 34

Threshold frequency

Answer 34

the minimum frequency of light needed to emit electrons from a certain metal surface

Question 35

Work Function

Answer 35

the minimum energy that an electron in the metal needs to be emitted from the metal surface