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 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

q=It

=7.5*45

=337.5C

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

I=0.7A

dividing by e the magnitude of charge on single electron we get

the number of electrons per second

=.7/(1.6*10^-19)

=4.4*10^18

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the rate of flow of electric charge across a given area is called current

I=dq/dt

the current density is the quantity whose direction is the same as current but magnitude is current per unit area.

J=I/A

I=integration of J.ds

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

let resistance of wire at temperature T0=R0

resistance of the wire at temperature T

=R

=R0+aR0(T-T0)

where a is temperature coffitient of the resistance of the material of the wire

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

R=roh(l/A)

where roh is a constant called resistivity

it depends in the material of the conductor

units=

R=ohm

roh=ohm.m

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the potential difference across a battery with a negligible internal resistance is equal in magnitude to the emf

as a charge passes from the baterry the non electric forces do work qE on it .

if q is +ve the +ve work

the electric forces on the other hand do an equal amount of negative work and the electrostatic system gains electric potential energy.

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the term internal resistance refers to the resistance within an emf source

a galvanometer is an instrument for masuring very small electric currents;

it underlies both voltmeters and ammeters.

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the electromotive force (emf) of a source is the energy per unit charge converted from chemical or some other form of energy to electrical energy

the emf is one volt when each coulomb of charge recieves one joule of energy.

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

by archimidies principle

roh1Vg=roh2(3V/4)g

this gives

roh2=4/3roh1

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

F1/A1=F2/A2

F1=200/5*250

=10kN

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

delta P=F/A

=5000/pi*r^2

=63700lb/ft^2

=44.2lb/in^2

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

before collison

L0=Rmv

after collision

Lf=(mR^2+I)w

L=Lf

w=mvr/(mR^2+I)

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

I0w0=Iw

I0=2Mr^2/5

I=2Mr1^2/5

w=(r/r1)^2w0

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

I1w1=I2w2

1.33*1.9=0.48w2

w2=5.26

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

power= tou*w

=.8{[1400(2*pi)]/60}

=117.3W

using 746W=1hp

P=0.157hp

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the power delivered by the moter is touw

therefore tou=.2/1400

=149/147

1.02Nm

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

net torque =(1600-500)*.4m

=440

net power delivered=tou * w

=440*10*pi=4400pi

net power generated=.9*4400w

=12.4kW

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

power=P=tou*w

P=2hp

=1492W

tou=1492/30*pi

1508Nm

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

the work done  by a xonstant torque in turning through an angle theta is tou*theta

then K of the wheel = work by stopping torque

so 1/2Iw^2=tou*theta

tou=.5*20*(6pi)^2/40*02*pi

=1401Nm

 Discussion Forums -> This Post 0 points    (0    in 0 votes )   [?]

KE=1/2Iw^2

I=Mk^2

=25*.22^2

1.21

KE=1/2*1.21*(12pi)^2

=860J

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