Equations to remeber

Question 1

percentage uncertanity

Answer 1

uncertanity
————- x 100%
measured value

Question 2

relative uncertanity

Answer 2

measured value

Question 3

average velocity

Answer 3

s
v = —
t

Question 4

equations for uniformly accelerated motion

Answer 4

v= u + aat

  (u+v) s= ------t
     2

s= ut + 1 at
–
2

v^2= u^2 + 2as

Question 5

speed time graph

• area under the graph
• gradient of graph

Answer 5

area under the graph =distance covered by an object

gradient of graph = acceleration

Question 6

weight

Answer 6

mg

Question 7

momentum

Answer 7

p = m x v

Question 8

conservation of linear momentum

Answer 8

(m1 x u 1) + (m2 x 2) = (m1 x v1) + (m2 x v2)

Question 9

elastic collision

Answer 9

the total Ek before the collision = the total Ek after the collision
1/2m1u1^2 + 1/2m2u2^2 = 1/2m1v1^2 + 1/2m2v2^2

Question 10

inelastic collision

Answer 10

total kinetic energy before collsion > total j=kinetic energy after the colilision

Question 11

newtoons 2nd law

Answer 11

F = ma

Question 12

density

Answer 12

V

Question 13

pressure

Answer 13

p = pgh

Question 14

upthrust

Answer 14

hpgA

Question 15

couple

Answer 15

F x d

Question 16

tourque

Answer 16

Fd sin(o)

Question 17

work

Answer 17

force x distance in direction of force

fscos(o)

Question 18

work done is spring

Answer 18

1/2Fx

1/2kx^2

Question 19

principal of conservation of mechanical energy

Answer 19

change of Ek = change of Ep

mgh = 1/2mv^2

Question 20

electric potential enegy

Answer 20

the quantity f charge in coloumb x potential difference

qv

Question 21

internal energy

Answer 21

Q = U + W

Question 22

power

Answer 22

P = Fv

Question 23

efficiency

Answer 23

useful energy output
——————— x 100%
total energy

Question 24

electrical equatiuons

Answer 24

E= V/d

I = Q/t

R=V/I

V= energy / Q

e.m.f = Ir + IR

P = (E^2 x R)/(R+r)^2

Resistance = (resistivity x L)/ A

resistance in series = R1 + R2 + R3…….

Resistance in parallel => 1/R=1/R1 + 1/R2 ….

Potential divider–> V1/V2 = R1/R2

                        --> V2 = ( R2/(R1 + R1)) X V

POWER = IV = I^2R = V^2 / R = ENERGY / TIME

Question 25

Pressure in liquid

Answer 25

p = pgh

Question 26

stress

Answer 26

F/ A

Question 27

strain

Answer 27

L/ x

Question 28

young modulous

Answer 28

stress / strain

Question 29

elastic potential energy

Answer 29

1/2 fx

1/2kx^2

Question 30

wave

Answer 30

v=f(wavelength)

f=1/T

Question 31

intesity of wave 1

Answer 31

I= P/A

I=kaA^2

Question 32

youg double slit experiment

Answer 32

x = (n x wavelength x D) / a

Question 33

diffraction grating

Answer 33

dsino = n x wavelength