Sabtu, 15 Desember 2012

Calculating work by Force in The Opposite with Displacement

calculating work by force in the opposite direction with displacement
 

a. understanding work
physically work is energy transfer through the force so that objects move
if the force f acting on a body that's as far as moving objects, the force f is said to be working for W. force and be an amount of displacement vectors. Thus work are scalar quantities mathematically written
           W = f. s


 with
f = force (N)
s = displacement (m)
W = Work done (j)


 B. work by the force in the opposite direction to the displacement

 

note the picture above the blocks work out force and friction F f. Friction opposite direction to the towing force acting on the block so that the work done is the following block
 work by the force is  
W = F cos F.s α = F. s cos 0 = F. s  
attempt by the force f is W = fs cos α = cos 180 = fs - fs. thus, the total effort is  
W = F.s - fs = (F-f) s
f friction direction opposite to the towing force F so that the frictional force f are negative.
when the total work on a block that moves on the surface of the plane's rough with displacement by the force F at an angle α to the horizontal plane and the frictional force f is
W = (F cos α - f) s


c. how to calculate this work?
to better understand, consider this example problems
If the external forces acting on a beam F = 5 N at an angle 37, the beam mass m = 1 kg, the coefficient of kinetic friction between the block and the base 0.2 with normal force 7 N, define
a. force friction
b. Total work if the move as far as 5 m
completion
a. friction
          fk = μk N = 0.2. 7 N = 1.4 N
b. total work
    W = (F cos α - f) s = (4 N -1.4 N) 5 m = 13 joule

 
Comments
5 Comments

5 komentar:

Rahmawati Yusri mengatakan...

Oh... Dynamic's apture.
May e you can to give other example about this matery ?

afni yunita mengatakan...

ok thank's..
but if the friction force significantly affect the business of an object??

aulia vasanty mengatakan...

hafiful,
what the dimension of the force?

Mulinda Dewi Lestari mengatakan...

why work is scalar????

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