Derived Quantites and their formula

Question 1

Area

Answer 1

A= length x length (m2) or l²

Question 2

Volume

Answer 2

V= length x length x length (m3) or l³

Question 3

Density

Answer 3

ρ = mass/ volume (Kgm-³)

Question 4

Velocity

Answer 4

v= displacement/ time (ms-¹)

Question 5

Acceleration

Answer 5

a = velocity/ time (ms-²) or dv/dt

Question 6

Force

Answer 6

F=ma (kgms-²or N)
Mass x acceleration

Question 7

Work aka energy

Answer 7

W or E = force x displacement (kgm²s-² or joules) or W= F by ∥x

Question 8

Power

Answer 8

P= work / Δtime (kgm²s-³ or watt)
elapsed time

Question 9

Charge or electric charge

Answer 9

Q = current x time (As or coulombs)

Question 10

Voltage

Answer 10

V= power/current (kgm²s-³A-¹)

Question 11

Speed

Answer 11

v= distance/time (ms-¹) or dx/dt

Question 12

Momentum

Answer 12

p = mv (kgms-¹)
Mass x velocity

Question 13

Pressure

Answer 13

p= F/A (Nm-² or pa) pascals

Question 14

Impulse

Answer 14

Change in momentum = applied force x elapsed time

Δp= F Δt

Question 15

List 3 dimensionless quantities

Answer 15

magnification, refractive index and relative density

Question 16

Relative Density

Answer 16

ρᵣ=ρₓ/ρᵥᵥₐₜₑᵣ (density of substance over density of water)

Question 17

Velocity

Answer 17

Δx/Δt displacement over change in time m/s

Question 18

Moments of a Force (T)

Answer 18

T=F by ⊥x or force by distance
Nm

Question 19

Torque due to a Couple (T)

Answer 19

T=C by x or force by distance
Nm

Question 20

Efficiency

Answer 20

η= (useful power out ÷ total power in) x 100%
= (useful energy out ÷ total energy in) x 100%
= Wₒᵤₜ/Wᵢₙ x 100%

Question 21

Gravitational potential energy

Answer 21

Eₚ= F by ∥x or
Eₚ= mgh mass of object x gravitational acceleration constant x height above ground
Joules

Question 22

Kinetic Energy

Answer 22

Eₖ= 1/2 mv²
half of an object’s mass (1/2*m) multiplied by the velocity squared.
Joules

Question 23

Mechanical Energy

Answer 23

Eₘ=Eₖ+Eₚ= constant energy in a closed mechanical system
Joules

Question 24

Gravitational Field Strength

Answer 24

g= F/mₒ
force/mass
Nkg-¹

Question 25

Weight

Answer 25

W=mg
Newtons
mass in kg
gravitational field strength in Nkg-¹

Question 26

angular velocity

Answer 26

w= dθ/dt
rads⁻¹
dθ- change in angular displacement

Question 27

gravitational potential

Answer 27

Φ= -GM₁/r
Jkg⁻¹
G- universal gravitational constant
M₁-mass creating gravitational field
r- distance from mass

Question 28

Power

Answer 28

P= Force x Velocity

Question 29

circular motion vs linear motion

Question 30

centripetal force

Answer 30

F= mv²/r = mω²r
mass x velocity2 / radius

Question 31

In centripetal force v²/r=

Answer 31

ω²r

Question 32

Centripetal acceleration

Answer 32

body’s speed v along the curve divided by the distance r from the centre of the circle to the moving body; that is, a꜀ = v²/r.

Question 33

Newtons law of gravitation

Answer 33

F=Gm₁m₂/r²

Question 34

Average velocity

Answer 34

v with a dash over it = total displacement (xₜ)/total time(tₜ) or u+v/2

Question 35

Newtons law of Gravitation

Answer 35

the force of attraction between two bodies mo and m1 is proportional to the product of the 2 masses and inversely proportion to the square or the distance apart ie F GM0M1/R2

Question 36

cRYSTALINE

Answer 36

metals

Question 37

amorphous

Answer 37

glass

Question 38

polymeric

Answer 38

rubber

Question 39

hooke’s law

Answer 39

F proportional to e
F=ke