Physics Help HERE ONLY !!

[Tutu_93]

october 2008 second variant

[Ghost Of Highbury]

paer 1, 3 or 6???

[nid404]

you take the mass of the beaker first and then the mass of beaker+water.

This will let u find the mass of the water( mass of beaker+water - mass of beaker)

And this is what u need other than the energy used to find sp.latent heat of fusion

[examsaresoon]

Could some one explain what "linearity" of a thermometer means?

[nid404]

This means it must change by the same amount for every degree of temperature change.

e.g. a property that changes a little in one half of the temperature range and much more in the other half would not be suitable

[Aodian]

can anyone post all the equations needed only for electricity, tranformers, CRO n pretty much anything to do with the electrical thingies.. I've wasted so much time trying to hunt down all those formulaes and equations in my books.. -.-'' thanks for the help in advance

[MaNa]

V= IR
P=VI
I= Charge/time
E=IV
Vs/Vp=Ns/Np where ( Vs= secondary output voltage
                               Vp= Primary inpu voltage
                               Ns number of tumrns in secondary coil
                               Np number of turns in primary coil)
IpVp=IsVs  (where Vp n Vs are same as above BUT Ip is Cureent in priamry coil Is is curent in secondary coil)
Power(loss) I^2 *R

 

[Shogun]

to find current,charge,time  interms of  charge ,current,time:
to find current (I)= charge(Q)/time(t)
to find charge (Q)= current (I) x time (t)
to find time (t)=  charge (q) / currebt (I)

to find resistance,voltage,current interms of resistance,voltage or current:
to find current (I)= voltage (v)/ resistance (R)
to find voltage(V)= Current(I) x rsistance (R)
to find resistance (R)= voltage (v) / Current (I)

formulas got to do with power and energy(workdone):
to find the power(p): voltage (v) x Current (I)   (the unit of power is watts)

to find the loss power: square of current x  resistance (I^2 x R)

to find energy(E) which is also workdone: voltage (v) x Current (I) x Time (t)    
                                               OR    
                                     power(p) x time(t) (unit of is joules)


formulas of transformer:
to find number of turns in secondary or primary coils OR the secondary or primary voltage:

 secondary voltge (Vs)        number of turns of secondary (Ns)
----------------------  =   ----------------------------------
 Primary voltage (Vp)           number of turns of primary (Np)


to find voltage or current in an 100% efficient trnasformer=

voltage in primary(Vp) x current in primary(Ip)  =    voltage in secondary(Vs) x current in secondary(Is)
                                                           OR
               power in primary = power in secondary (cuz voltage(V) x current (I)= power)

more resistance formula:
to find total resistance aranged in SERIES : just add all resistance (R1+R2+R3),etc
to find tpatal resistance where resistors are arange in parallel : just add 1/r
      (1/R1  + 1/R2  + 1/R3 = 1/R) etc then at the end reverse it by making  1/R to  R/1 to get (R) resistance

and no formulas for CRO

well thts all i guess
any confusion or help u need just ask me

[Aodian]

Thanx a lot Manah and Shogun!

[MaNa]

Thanx a lot Manah and Shogun!

No problem but dont forget + rep 

[Aodian]

Thanx a lot Manah and Shogun!

No problem but dont forget + rep 

lol no problem.. but still a noob here lol.. so show me how to add rep

[Aodian]

nvm i found it lol.. it didnt show earlier but i got it

[Bani]

2a) put different value of masses on bothe sides of the pivot  but make sure tht after using the formula (fxd) (where

f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)

 the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side,  add mass 100g on the second hole (with disatnce 8 cm from teh pivot)

so when using the formula "fxd " u get on one side: 200x4=800N
                                                     and                                       
                                                   on the other side: 100x8=800N
                         - see both have the same product so it is now they are balanced(in equilibrium)


ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.

c)use formula "fxd"
               200x4=800N
               100x8=800N

d)this is the force of pivot which is downwar to get tht simply add the masses u put
100+800=900g

but rmember u can choose any mass at any distance but the product with equation "fxd" must be same

thts all,hope this helped, any confusion or difficulties or help u need, im all here

Hey,the formula for calculating the moment is f*d, and when we multiply 200g by 4cm, aren't we multiplying the mass by the distance? Aren't we first suppossed to convert the mass into force by multiplying it with 10 (F=ma)? and the unit for moment is supposed to be Nm, isn't it? Please help. Thanks in advance

[hala999]

hey guyz !!!
i need help wid nov 08 1st variant q 5 c

(c) Using a 40 W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched
off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the value of the specific latent heat of fusion of ice from these results.

[emi]

L = 40*120/16.3-2.1  = 338.02 J/g

change the minutes to seconds , subtract the first and final mass of ice melted and simple divide with energy